You mean the "release date"? That's an oversight with Amazon that I'm frankly amazed they haven't fixed yet. If something has been announced but they don't know the release date they just list it as December 31st, and as that date draws near they bump it out a year. They really should have a way to say the release date is unknown, or at least list the date as being a several years out. Although since they also don't charge until just before shipment, there's no real harm in someone getting confused and placing an order. If you meant something else- uh, sorry for the mini rant?
I am pretty sure that amazon has been writing release dates for quite some time that are wrong. Unless you've seen it confirmed in a trailer or something, never trust it. Especially if it's "December 31st" I don't know how many times I've seen games with that particular release date.
