He might have been, and I did always like the Goober character. But I remember on sitcomsonline.com, on The Andy Griffith Show board, a poster said he recently attended an appearance and autograph session by G.L., and when his turn in line came up, G.L. looked at him and asked "Haven't I seen you here before?" then added "You only get one book and one autograph." He continued to claim the poster was trying to get another autograph; I don't remember whether he claimed he intended to sell it, or he just implied that, but he continued to argue contemptuously (or so claimed the poster).
I've read many stories like this before, certainly including about Andy Griffith and how he is rude and nasty to fans who recognize him and want to say a personal hello. But the fact is, celebrities get to the point where they can't go out in public without being recognized, and there are fans who want a 'piece of them' in some way, so naturally they come to resent that situation. Perhaps even more so when their very identity is largely lost to a character they played and they're relegated to being remembered for that character, most likely very unlike the true person.