I'm not seeing anything that will infringe on the screen count. Hunger Games will be in it's fourth week, so it will be starting to drop screens. The good Dinosaur will be in week 3, and is a Disney property and they can rob screens from it unless it's still going strong. Theres nothing else that week or in the month before that has any blockbuster potential. They'll have no trouble getting whatever screens this calls for. That and December openings don't hardly ever have huge openings. It's all about the legs and how the 2nd, 3rd, 4th, etc weekends plus holiday weekdays do. Unless the movie just is terrible, it'll be the biggest December opening ever, and should easily hit $350+ million domestic. After that, it just comes down to how many people want to see it and how much buzz it creates. Remember, this is the same opening day that Avatar had. It only opened to $77 million, but went on the be the biggest movie of all time. I'm not expecting this to hit $700 million, but $500 + is certainly within reason.
Sorry for the box office tangent. lol