Yes, but before the Super Bowl the season, including the championship, would be over before the New Year. In 1973 the Super Bowl was played on January 14th.
I have a vague recollection of watching what I think was a championship game in the mid-60s at Lambert Field with snow flying, you could barely see the ground. I know it was over at least by New Years for the Giants then, too, because I recall my younger and charmingly ditzy sister going to a New Year’s party and upon her return noting that a “football guy, Whitey Piddle” was there. It was Y.A. Tittle.