“The Dark Knight” will sell an incredible $77 million worth of tickets this weekend based on Friday numbers, says Steve Mason of Fantasy Moguls who is predicting the Caped Crusader will pass “Iron Man” as the top grossing flick of the year by Monday morning with $315.6 in domestic grosses by Monday morning. Just last Monday, the New York Times said that Chris Nolan’s sequel to his reboot probably couldn’t top the $450 million worth of North American tickets sold by Tim Burton’s 1989 blockbuster when that figure is adjusted for inflation. Well, maybe it can. Mase predicts “Step Brothers” will do $33 million for the weekend, which is around $14 million less than “Talladega Nights” but slightly more than manboy Will Ferrell’s No. 2 opener, “Blades of Glory.” Holding strong at No. 3 is box office queen (!) Meryl Streep’s “Mamma Mia!” with a predicted $17.6 million. “The X-Files: I Want to Believe” is opening well under expectations, and Mase figures it will have to settle for a $12 million weekend — an unusual third straight flop for Fox after “Meet Dave” and “Space Chimps.”