So the guy in I mentioned in the OP said GT5 would be playable at GDC and he was indeed correct. I jumped the gun and posted my reply too quickly while just skimming the article. GT5 will be playable and then off to TGS.
Thank you again jin_shihouin and I am very sorry.
Edit - Gamescom not GDC, seriously Gran Turismo does things to me. :/