The steel of that frame looks very much like the Super models I sold a bunch of in the early 1980s. Creases, Colnago stamped in chain stays, top eye plugs, etc.
However the paint job is very odd. That decal on the top tube is really strange. If I had first seen that frame cold, i,e., never having read all that blather about it in that eBay ad, I would have guessed the British painting company Colorworks (is that it? The guys who paint the Omegas, Donahues, etc) had redone it... The color masks used with airbrushing is very untypical of the early 80s. That is more like 10 years or more later.
But who knows as Colnago has made a lot of bikes and could have done this. I bet it is a 1990s frame though and I bet Bepe Sarronni never set eyes on it.
Dale Brown
Greensboro, North Carolina