No. This is a PS3 game and GT6 is not being released on PS4. It MIGHT be playable on PS4 when Sony's cloud streaming service is working and GT6 is added to the list of supported games. At E3 Sony stated the cloud streaming service would not be available until "2014"
It is very incorrect. GT6 is NOT being ported. GT6.5 probably even GT7 will be the PS4's first GT game. Polyphony have themselves said they would not release on PS4 with such a paltry user base upon release.
Where do you get the idea it will have a "paltry user base at release"? You do realise how many consoles these companies shift at launch worldwide? Hardly "paltry" numbers, and the PS4 is likely to sell more than the PS3 did at launch because of all the fuss around Microsofts backfired tactics.
Polyphony Digital have said they are developing a Gran Turismo game for the PS4 but its likely to be some time before release. Its more likely it will be called Gran Turismo 7 & not a straight port of this version.