Yeah at that time the Cowboys wore their blues once or twice per year. I seem to remember the Skins wearing whites at home, requiring the Boys to wear their blues . I also believe the Eagles went through a period of wearing Whites at home too. I wondered in my youth if any teams switched it up at home against the Cowboys just to get them out of their patented whites.
Here’s a little history I just looked up. The Cowboys have worn whites at home since the early 60’s. In Super Bowl 5, they were the home team and wore their blues. They were forced to do so by NFL rules.
“As the designated home team, Dallas was forced to wear its blue jerseys for the Super Bowl under rules in place at the time, which did not allow the home team its choice of jersey color, unlike the regular season and playoff games leading up to the Super Bowl. Dallas had not worn its blue jerseys at home since
1963, as Cowboys general manager
Tex Schramm opted to have the team wear white at home in order to present fans with a consistent look. The Cowboys wore their blue jerseys twice during the 1970 season, losing 20–7 at
St. Louis in week three and winning 6–2 at
Cleveland in week 13. The designated home team was first allowed its choice of jersey color for
Super Bowl XIII, allowing the Cowboys to wear white vs. the
Pittsburgh Steelers.”