Not exclusively, it also means "(own, self, voluntary) will, as...(what) would"
Here are a few commentaries I read on this verse. I am not certain it is as clear cut as you state.
Jamieson, Fausset, & Brown
If any man of you bring an offering unto the Lord--The directions given here relate solely to voluntary or freewill offerings--those rendered over and above such, as being of standing and universal obligation, could not be dispensed with or commuted for any other kind of offering ( Exd 29:38 Lev 23:37 Num 28:3, 11-27 , &c.).
Matthew Henry (Lev. 1:3)
2. The owner must offer it voluntarily.
Geneva Study Bible
1:3 If his offering [be] a burnt sacrifice of the herd, let him offer a male without blemish: he shall offer it of his own voluntary will at the door of the c tabernacle of the congregation before the LORD.
J. Vernon McGee
“He shall offer it of his own voluntary will.” May I say, this is free will with a vengeance. The Lord Jesus said, “if any man thirst, let him come…” . This is an lll-inclusive invitation to the human family. None are excluded except those who exclude themselves.
It only refers to will in relation to desire. The word "free" is nowhere in the Hebrew, nor is it implied. Just because an offering is "voluntary" does not mean it is a desire free from outside influence.