To be honest, GAME are bollocks.
The people they employ don't know shit, their information is totally unreliable. They're only posting a 'fill - in date' to encourage people to preorder, just like EVERY SINGLE OTHER SITE is. If i went into one of their stores tomorrow, they'd still be like: 'Sorry, mate, no idea.'
Sorry to burst your bubble, but they're probably relying on speculation, or, guessing.
Just looked, the release date for the PS3 version is just '2008' , so, it's pretty much guaranteed to be bullshit / guesswork.