Visible crew/equipment: At the end, when Dillion drives to talk to David, you can see the crew reflected in the rear panel of the car.
Other mistake: It would have been extremely rare for Christian males to be circumcised during the time period of this film. Since David and his family are practising Jews, he would have been circumcised. Since all the boys at the school shower in a big group shower, they would have known and/or suspected David was Jewish from day one.
Visible crew/equipment: During the football game, in one of the huddles, the boom mike is reflected in Dillon's helmet.