North Hills Senior High School, where Brendan taught physics, and the Twin Highway Drive-in theater, where his students watched the final two fights, take place in Philadelphia but are actually located in Pittsburgh, where most of the rest of the movie is set.
When Paddy tells Tommy that he'll leave the coffee out until 0500 hours (5:00am), a digital alarm clock in the background reveals that the time is already 5:23am.
Paddy may have been speaking in reference to future awakenings but this doesn't sound like the case, however, Paddy says that climbing the stairs hurts his knees and so it's likely he doesn't go up there often, thus, the clock may still be set on summertime.
(Flopped shot) During the final bout, Tommy looks over at the crowd of U.S. Marines. All of their ribbons are mounted over their left side. when shown again they are on the right side and in the last shot there on the left side again.