lol this is actually from the fourth game, escape from monkey island, for ps2 that was in 3D.
I found a production sketch of him as well as some of the other characters

I like it how they change their styles for each game, in the third monkey island game
curse of monkey island, the 2D one, that I burth for ya. they have really skinny limbs or whatever.

in the 3D one they've tried to keep the style but wow does guybrush look younger? lol
im gonna bring escape from monkey island so you can try it out.