Neat poll! Unfortunately I literally can't answer it though, because I honestly don't know what version was used to introduce me to the game! It was circa 1987-ish, so either 1e, some version of Basic, or OD&D. If I had to guess, I would say probably a boxed set, but I have almost zero way of ever finding out for sure.
I can say this much: I remember a picture from the rule book showing a thief with a dagger mugging some dude, in black and white. I also remember asking one of my fellow players about playing a Thief, and he said something about thieves Strength scores being limited to 16 or less (so of course I shouldn't play one, lol). He may have been misinformed, so I don't even know about the validity of that.