The filmmakers must have been Steeler fans....
Ahh, the days of the Dallas-Pittsburg Dynasties. Bradshaw & the Steel curtain were picking apart Staubach & the Cowboys before those blasted terrorists interrupted the Super Bowl, Lol.
They must have been using 1976 footage. In 1977 Dallas won the Super Bowl over Denver. By the way the Steelers did win but never blew out the Cowboys. Every game was decided by 4 points- and Cowboys got revenge in 1996!
shareActually in 1977 the Raiders beat the Vikings. Dallas won in 1978
shareThe 1977 season Dallas won is what he meant.
Overall production of the film took more than a year to finish after the Super Bowl scenes were shot at Super Bowl X in January 1976 (hence the reason why you see a number of Bicentennial symbols at various points). Because the final delays in completing the film extended to early 1977 after the election of Jimmy Carter, that's why Frankenheimer then did a new insert showing a Jimmy Carter lookalike arriving at the game.