It doesn’t happen often, but “The Hangover” and “Up” reversed their rankings by the narrowest of margins when the “final” box office numbers came out today. “The Hangover” and “Up” both posted better numbers than the estimates on Sunday, but this time around “The Hangover” led with $44,979,319 to $44,138,266 for “Up.” Meanwhile, “Land of the Lost” shrank to $18.8 million. The estimates released on Sunday are based on Friday and Saturday numbers (extrapolated from a sample), with the Sunday numbers estimated based on historical models. Any time two titles are separatedly by a million or so, it’s possible their position will reverse in the “actual” Friday-through-Sunday numbers released on Monday. These numbers also rely on extrapolation, since no system exists to accurately track sales at every movie theater in the country. It’s also quite possible that some teenagers bought tickets to the PG-13 rated “Land of the Lost” and snuck into auditoriums showing the R-rated “The Hangover.”