Even the more conservative predictions by Gitesh Pandya at Box Office Guru are impressive after six weeks in the box-office wilderness. Pointing to one of the fall season’s few successes, the family-driven “The Game Plan,” which far exceeded expectations, Gitesh calls the weekend for “Bee Movie” with $42 million and thinks the 167-minute running time of “American Gangster” will hold the gross down to $34 million — still a home run for a serious movie starring Denzel Washington and Russell Crowe. Neither of the forecasters mentioned it, but I will: another possible complicating factor for “Gangster” is the widespread availability of high-quality pirate DVDs on the streets, apparently derived from a copy of the flick that turned up on file sharing sites last week. “One of the best bootlegs I’ve seen,” a guy at the gym told me yesterday.