No... their is a difference between a GFW title and a GFW LIVE title. Many games are GFW title but thats just means that they have to meet certain settings/options put in place by MS such as a certain amount of screen resolutions, XBOX 360 controller support etc. That doesn't mean that it supports Live (Achievements, Gamerscore, Friends list, Messages etc). However, if its a GFW Live game (Gears of War, Viva Pinata, Fallout 3, Shadowrun etc) then it WILL support all of the features found in the 360 version so you can add to your Gamerscore and still communicate with gamers on your XBOX Live friends list cross-platform. Now try to follow me here... Even if a game is a GFW LIVE game it still doesn't mean that you can PLAY cross-platform between 360 and PC users (thats a decision made my the devs) but you will still have the ability to communicate with them by sending/receiving messages (voice, text) and still adding to your Gamerscore by getting Achievements.
What Im saying is that I hope that 2K makes the PC version a GFW Live game AND includes cross-platform play with 360 users (which will still have the biggest community of gamers playing this game online) so that all will be well for me and I dont feel isolated from my XBOX Live friends.