If they recreated it for a movie, and odds are pretty good that Sam Mendes will do just that in one of the four biopics he’s working on, The Beatles’ final, legendary rooftop gig would probably include lots of scenes of everyday Londoners popping their heads out of office windows and black cabs, marveling at the joyous sounds coming from the top of the Apple Corps building on Savile Row. To be sure, as the wealth of documentary footage from that…