So "post merger" would be past 1970 and on. So that excludes the Packers. After that,,,,,,,,,,Miami, Pittsburgh, Pittsburgh, San Francisco, Dallas, Denver, New England. So no we would not be the first "post merger".
To your point, There have been 6 NFL expansion teams since the "merger" 3 have won a Super Bowl. Baltimore should not be considered an expansion team. So basically Tampa Bay and Seattle who in all reality have each won 1 Super Bowl.
With all due respect this is not a big deal. However the bigger story would be not only our franchise winning another Super Bowl but the first to repeat since the 2004 season. 10 years!
So in 39 years 7 teams have repeated. So since the Patriots last Super Bowl win, the average was ever 5.5 years there was a repeat champion
If we repeat,, yes big story. First expansion team since the "merger" no.