Sure I remember Bert and Harry. Funny as hell. IIRC, they and gillette shaving blades were the advertisers for the friday night fights.
Even though I was just a little kid then, I can still remember the theme song to the FNFs and they would show the big Gillette logo during the intro. I think Ballantine beer was also a sponsor when Three Ring Pete was their advertising icon.
Yep, it would flash to signal which round was upcoming. I recall following the career of Joey Archer, a better than average middle weight. That my friend, was many moons ago :)