I do recall how some Bills fans were back then and yeah at times wasn't a pretty sight, but I wouldn't say any worse than some of what we see today. Maybe the long drought might have made some (not all) change their act.
As for the bold, imo I think if Bills win a SB most/majority would handle graciously. Still will always have those fans for every team here and there that are a-holes. But with all the frustrating years of losing, I think a lot of Bills fans would react a lot better than you think.