You'll have 4.0.3 downloaded, which is a version of Beta ATM, not actual Cata. You'll still end up having to download the actual Cata patch after you get your CD key. If you did the digital pre-order then you'll get your key code and be able to download everything ahead of time anyways. Cata live doesn't launch until 3 AM eastern, 2 central, 1 rm, and 12 west,,, so if you're on the east coast you can go to gamestop at midnight, pick up your game, instal, download the patch, go to sleep for a couple hours, then be ready for your levelign grind.