right, I was trying to gather clues to narrow down the possible year, and since it's got:
the portacatena holes in the Campy dropouts
the top-of-BB cable guides
the single water-bottle bosses
recessed Allen-head brake mountings on both the frame and the (not original) fork
it's clear that the decals can't be trusted, that Columbus decal would indicate an earlier frame, but this has to be late '70s to early '80s. I guess that the rest of the decals might be not original, too, and they were reminding me of something from a big maker like Bianchi who sponsored a lot of racers (and won many years in a row). I still think this is from a smaller-output concern, but most probably made from Columbus SL tubing and high quality.
Next question: any numbers or stampings of any kind on the BB shell or anywhere on the frame?