They have since removed the date though. Still listed as PS3 title.

http://www.newegg.com/Product/Product.aspx?Item=N82E16879261422&nm_mc=AFC-C8Junction&cm_mmc=AFC-C8Junction-_-na-_-na-_-na&cm_sp=&AID=10446076&PID=6149513&SID=13xl5gxwdr1i3

UPDATES:

A couple of sites have it listed for PS4 as well:

http://www.webhallen.com/se-sv/spel/playstation_4/170495-gran_turismo_6
http://cdon.se/spel/gran_turismo_6-22902898

A set of photos on a Facebook page of a car manufacturer shows vehicles being scanned for inclusion in 'Gran Turismo PS4'.

http://www.nowgamer.com/news/1844158/gran_turismo_6_on_ps4_leaked.html

Launching your new console by releasing your biggest franchise on your old console... genius.

I still think putting GT6 on ps3 is a mistake(if true). Of course the ps3 has a big install base, but if GT6 was at least in the launch window of ps4 then it would sell a lot of ps4's

A couple of sites have it listed for PS4 as well:

http://www.webhallen.com/se-sv/spel/playstation_4/170495-gran_turismo_6
http://cdon.se/spel/gran_turismo_6-22902898

A set of photos on a Facebook page of a car manufacturer shows vehicles being scanned for inclusion in 'Gran Turismo PS4'.

http://www.nowgamer.com/news/1844158/gran_turismo_6_on_ps4_leaked.html

Looks Swedish to me!

I dunno. I can see them releasing it on PS3 only since they already have DriveClub for PS4.

What's the difference? :P 

Ok, ok, I'll edit it...

Didn't Nintendo do the same thing with Twilight Princess?

OT:  I highly doubt this "rumor", 1 because if a new GT were in fact coming this year or shortly after the PS4's launch, we would have seen it at Sony's PS4 press conference instead of that other racing game with the dude that had an unhealty obsession with upholstery, and 2) it's taken an average of nearly 5 years for each new installment to be released since the beginning of the 6th gen.

No difference, of course. I just like being pedantic.

please be untrue! PLEASE!!