If you read Red Eagles, which tells the story of the USAF's secret squadron of MiGs used for aggressor training, both VF-41 crews who scored that day had flown against the "tame" MiGs, which the Navy aircrews who flew in 1972 over NVN did not have.....I wouldn't be surprised if fighter pilots who scored in 1991 had received similar training prior to deploying. It's interesting to note that after German reunification, an EGAF MiG-21 wing was kept active for several weeks, as was a MiG-23 wing, along with the MiG-29s. (hint, hint....)
Some Navy crews by 1972 had definitely flown against US operated MiG-17's and 21's as part of the Have Doughnut, Have Drill and Have Ferry programmes. Indirectly the knowledge gained from these evaluations was being disseminated at NFWS/Topgun as early as 1969-70.
Luftwaffe MiG-29's hung around until 2003 when they were passed on to Poland