The movie shows the Bears playing the Atlanta Falcons in Atlanta during the 1965 season but the Falcons didn't start playing until 1966.
Game footage shows the Bears hosting the Lions in a night game. Until the 1971 season the Bears played their home games at Wrigley Field. Lights weren't installed at Wrigley until 1988.
During their first conversation in George Halas' office, Halas asks Gayle Sayers if he did any pass-catching in college. As a first-round draft selection, Sayers should have been thoroughly scouted by the Bears' organization; Halas should have known Sayre's capabilities almost inside-out.