DCT: I doubt it since there are a few compatibly fixes for C2 plus GOG has a deal with nglide so that takes care of the 3dfx support. The only real issue I know of and had experienced is the lack of music in game on windows 7.
The music (which is in a form of normal audio CD tracks) plays fine at least on my Win7/64bit machine. But the problem with the re-release would probably be that it isn't only game music, but real music (mostly Iron Maiden I think, "Aces High", "The Trooper" etc.).
I'm not a lawyer, but I presume Stainless Games can't freely distribute the music, so maybe the possible GOG version would ship without music, or some replacement music. Which would be fine to me, the game is nice even without the music, or if you prefer, you can always pop in your Iron Maiden or other hard rock CD and play it in the background while you are crushing pedestrians.
I think I'll add the steps how to make the game (Carmageddon 2) Win7 compatible to the other discussion...
EDIT: Done:
http://www.gog.com/en/forum/general/old_games_that_are_really_hard_to_fix_and_your_soltuions/post5