Total newbie here and new to this Brand as well. I bought a Bordeaux Red AD bike at a local pawn shop 3 weeks ago in ride able condition. It's a 531 frame and forks with no model name and mostly Campy Super Record components. My serial # is 5749014 which seems "75" to "77"ish but the components seem to be 1980 or so. I'm guessing an older frame set was purchased then built up with selected components. I'm riding it daily since it came back from the bike shop and I love it! I will replace the non-Campy stuff with correct Campagnolo components for the Ultima of 1980 vintage. Love this forum by the way!