The blackout policy (it was never a rule) was changed at the start of the 1973 season and several Bills home games were on local TV that season. Don't know about the Philly game though.
You can thank President Richard Nixon for strongly urging the NFL and Congress to change the pre-1973 policy. Nixon, a fervent football fan, could not watch the 1972 NFC championship between the Redskins and Cowboys because the game was blacked out in Washington, despite being sold out. Nixon's prodding led the NFL to install a policy where if a game was sold out 72 hours before kickoff, it could be shown locally. Thankfully, this revamped policy was abandoned several years ago, where now every home game is shown locally, sold out or not.