Both of those are somewhat, but not entirely true. There were repeats, but most of the matchups were based on the standings from the previous season.
From 1978-87:
5-TEAM DIVISIONS IN AFC/NFC
1st: Games vs. 1st- and 4th-place finishers in other two divisions, plus games vs. top 4 finishers in one division in other conference (out-of-conference games rotated every three years)
2nd: Games vs. 2nd- and 3rd-place finishers in other two divisions, plus games vs. top 4 finishers in one division in other conference
3rd: Games vs. 2nd- and 3rd-place finishers in other two divisions, plus games vs. top 4 finishers in one division in other conference
4th: Games vs. 1st- and 4th-place finishers in other two divisions, plus games vs. top 4 finishers in one division in other conference
5th: Two games vs. other fifth-place finisher, one game each vs. entire four-team AFC Central, one game each vs. fifth-place NFC finishers
4-TEAM DIVISIONS IN AFC/NFC
1st: games vs. 1st- and 4th-place finishers in other two divisions, games vs. two fifth-place finishers, plus games vs. top 4 finishers in one division in other conference
2nd: games vs. 2nd- and 3rd-place finishers in other two divisions, games vs. two fifth-place finishers, plus games vs. top 4 finishers in one division in other conference
3rd: 1st: games vs. 2nd- and 3rd-place finishers in other two divisions, games vs. two fifth-place finishers, plus games vs. top 4 finishers in one division in other conference
4th: games vs. 1st- and 4th-place finishers in other two divisions, games vs. two fifth-place finishers, plus games vs. top 4 finishers in one division in other conference
This was tweaked in 1988 to make the schedules tougher for the first-place teams. They went from playing fourth-place teams to one game vs. a second-place team and another vs. a third-place team. Plus, there were some other tweaks to the formula. But for the most part, scheduling was dependent on how you finished the previous season.
Starting in 2002, 14 of the 16 games have been known years in advance. Only two games are dependent on where you finish. The other eight non-division games are four against one division in your conference and four against a division in the other conference. Which division you play rotates from year to year, but even the game sites for 2009 were known in 2002 for these games.

