It’s incredible what can happen when a game is so popular and so anticipated. Take the PC GTA 5 version. A reddit user has done a bit of sleuthing in the PS3 version of GTA V and has discovered various references to PC, DX11 and x64. You can view the technical details, but as Hal_Nein_Thousand says, it proves that the PC version has been worked on along side the console version almost since the beginning. I think that’s the key here.
There is no official word from Rockstar about a possible GTA 5 PC version although there have been numerous online game stores posting preorders for a PC version in addition to some of those pre orders being estimated with a shipping date in November 2013. All speculation at this point, but it does seem more and more likely that a 2013 release is possible.