They profess belief, Christ makes it clear they yet do not.
We see this as fact here, as Peter once again fights for the temporal Kingdom promised to Israel:
John 18:10-11
King James Version (KJV)
10 Then Simon Peter having a sword drew it, and smote the high priest's servant, and cut off his right ear. The servant's name was Malchus.
11 Then said Jesus unto Peter, Put up thy sword into the sheath: the cup which my Father hath given me, shall I not drink it?
Christ identifies his (Peter's) actions as trying to avert Christ going to the Cross ("...the cup...shall I not drink it?").
And again, clear indication Peter is not a believing born again Christian...
Matthew 26:71-74
King James Version (KJV)
71 And when he was gone out into the porch, another maid saw him, and said unto them that were there, This fellow was also with Jesus of Nazareth.
72 And again he denied with an oath, I do not know the man.
73 And after a while came unto him they that stood by, and said to Peter, Surely thou also art one of them; for thy speech bewrayeth thee.
74 Then began he to curse and to swear, saying, I know not the man. And immediately the cock crew.
Born again?
No. Unregenerate.
Christ makes that clear:
Luke 22:31-33
King James Version (KJV)
31 And the Lord said, Simon, Simon, behold, Satan hath desired to have you, that he may sift you as wheat:
32 But I have prayed for thee, that thy faith fail not: and when thou art converted, strengthen thy brethren.
33 And he said unto him, Lord, I am ready to go with thee, both into prison, and to death.
We see that Peter, after Christ's death, somewhat petulant, here...
John 21:14-18
King James Version (KJV)
14 This is now the third time that Jesus shewed himself to his disciples, after that he was risen from the dead.
15 So when they had dined, Jesus saith to Simon Peter, Simon, son of Jonas, lovest thou me more than these? He saith unto him, Yea, Lord; thou knowest that I love thee. He saith unto him, Feed my lambs.
16 He saith to him again the second time, Simon, son of Jonas, lovest thou me? He saith unto him, Yea, Lord; thou knowest that I love thee. He saith unto him, Feed my sheep.
17 He saith unto him the third time, Simon, son of Jonas, lovest thou me? Peter was grieved because he said unto him the third time, Lovest thou me? And he said unto him, Lord, thou knowest all things; thou knowest that I love thee. Jesus saith unto him, Feed my sheep.
18 Verily, verily, I say unto thee, When thou wast young, thou girdest thyself, and walkedst whither thou wouldest: but when thou shalt be old, thou shalt stretch forth thy hands, and another shall gird thee, and carry thee whither thou wouldest not.
And we see Peter, and the other disciples...still in need of the Baptism with the Holy Spirit.
And this on the Day of the Lord's Ascension:
Acts 1 
King James Version (KJV)
1 The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach,
2 Until the day in which he was taken up, after that he through the Holy Ghost had given commandments unto the apostles whom he had chosen:
3 To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God:
This is spoken the Day He was taken up:
4 And, being assembled together with them, commanded them that they should not depart from Jerusalem, but wait for the promise of the Father, which, saith he, ye have heard of me.
"Wait for the promise of the Father..."
In view are the promises given to Israel (identified as such in v.6) in the Old Testament.
"...which, saith He, ye have heard of Me." 
We can read about His teaching on the Promised Spirit decisively in John 14-16, which is prophetic, and speaks clearly about the coming of the Comforter which Christ makes clear could not be sent except He return to Heaven from whence He came.
Now consider the next statement:
5 For John truly baptized with water; but ye shall be baptized with the Holy Ghost not many days hence.
I will just say in fleeting that John spoke of the Christ, and that Christ, the Baptizer, would baptize with fire (judgment) and the Spirit (salvation). As you mentioned oil being representative of the Holy Spirit in regards to the Two Witnesses, and I responded that this was an Old Testament usage, and that water was the New Testament picture of the Word, even so here, fire is not representative of the Spirit, but of judgment. And I may throw that in after we look at this text.
The point to consider is that the Baptism with the Holy Ghost has not taken place yet. No denying that, it is all too clear. And while some see this as empowerment, that is not the case, as we will see as we go.
Now we will see what is probably the most misplaced and misguided question in all of Scripture:
6 When they therefore were come together, they asked of him, saying, Lord, wilt thou at this time restore again the kingdom to Israel?
As born again believers our reaction to this question is..."What?! You mean to tell me the Lord has just told you that you will be baptized with the Holy Ghost not many days hence...
...and you savor the things which be of the flesh?"
That is what is in view here. That is what Peter hoped to "help" establish by keeping Christ from dying. He did not understand that Christ was there to die for his sins, but he did understand...
...the promises of God.
Which promised Israel the Kingdom would be restored unto them.
The Lord does not deny the promise of God, but states...
7 And he said unto them, It is not for you to know the times or the seasons, which the Father hath put in his own power.
"...it is not for you to know when that will take place."
8 But ye shall receive power, after that the Holy Ghost is come upon you: and ye shall be witnesses unto me both in Jerusalem, and in all Judaea, and in Samaria, and unto the uttermost part of the earth.
"...after that the Holy Ghost is come upon you."
It is being Baptized with the Holy Ghost that would establish the empowerment to...
...preach the Gospel.
There will be a change in the preaching of the disciples after they are Baptized with the Holy Ghost, for they will begin preaching the revealed Gospel of Christ.
We do not, as you intimated in previous posts, see this as "another Gospel," but the same Gospel that has been progressively revealed throughout Scripture. The disciples were not privy to the Gospel of Christ any more than the Prophet Isaiah was. Used to prophesy, yes, but so was Caiaphas, who also had no clue as to what he was saying...
John 11:49-51
King James Version (KJV)
49 And one of them, named Caiaphas, being the high priest that same year, said unto them, Ye know nothing at all,
50 Nor consider that it is expedient for us, that one man should die for the people, and that the whole nation perish not.
51 And this spake he not of himself: but being high priest that year, he prophesied that Jesus should die for that nation;
We don't, as those Prophets, inquire, we have had the Gospel revealed to us by the Comforter.
That is how we are saved:
John 16:7-9
King James Version (KJV)
7 Nevertheless I tell you the truth; It is expedient for you that I go away: for if I go not away, the Comforter will not come unto you; but if I depart, I will send him unto you.
8 And when he is come, he will reprove the world of sin, and of righteousness, and of judgment:
9 Of sin, because they believe not on me;
The Comforter ministers to the lost, enlightening them that they might understand, believe, and embrace the Gospel of Jesus Christ.
No man knew this mystery prior to Pentecost, not even the disciples, who we can see, if we look, were without understanding and even in opposition to the Gospel, and Peter illustrates this best in his attempts to keep Christ from the Cross.
And since this has gotten a little long, we can save a discussion about Matthew 3, John the Baptist's warning of impending judgment, and of Christ's Baptizing with the Spirit, which we see is a future event.
If you will only give this consideration, I assure you it will change how you understand Scripture. The above is indisputable. Christ is the Firstborn from the dead, and He is the only one that has been glorified at this point. We know from Paul's teaching that the dead in Christ rise first, and that has not taken place yet. 
Continued...