In his CV (now pulled, but uncovered and pictured by Joystiq) character animator at Rockstar North, Alex O'Dwyer, may have accidentally revealed the current planned month of release for Grand Theft Auto V.
I say "planned" because even if this is the current word on when GTA V will lauch, I higly doubt it's locked down. The franchise is no stranger to delays and you must consider the games already on Take-Two's plate.
They have Max Payne 3, Borderlands 2, and BioShock: Infinite all confirmed to launch this year with dates in place. That's a lot of games for a publisher famous for supporting six year development cycles and who also have no titles yet announced for 2013. October would also put GTA V and BioShock in competiton with each other (though I wouldn't say directly).
My money is on the date being tentative with the team fully prepared for a delay. The fact the CV was pulled is certainly telling, but who really knows? One thing is certain, however: people want Grand Theft Auto V as soon as possible.