Yeah I think amazon are mistaken, you're right, everywhere else says october 3. Probably a devious marketing ploy to secure some pre orders, I'm waiting for my notification from amazon that the release has slipped to october 3. I'll pretend I'm surprised!!
Amazon's a great site, but for getting video game pre-orders I wouldn't recommend them, their despatch times are iffy, sometimes they come early, sometimes they take a few days more, even with paying for 1st class you can't be sure you'll get it in time for the weekend.
If I were you I'd preorder at GAME, on their website, they send them out usually to arrive on the actual release date, they use first class post, it's free, and with a reward card scheme you get 5% of the value; in reward points on all preorders, so £40 games give you £2 worth of points to deduct off the price of the next game you buy! (or even more if you let them accumalate)
Are you listening Amazon? how about a reward card scheme like GAME have?