Originally Posted by
Sangetsu
My old Atala was made with Columbus steel, the top tube was faintly stamped with the Columbus emblem a few inches behind the headset. Normally, the Columbus sticker would be located just above the "Handmade in Italy" sticker.
Until the early 80's Columbus marked the long-butt end of their tubes with the dove emblem to indicate the end from which to trim the tube. Thus you're more likely to see these stampings on large frames than small.
After the early 80s Columbus marked their tubes with a graphite discharge electrode instead of stamping them.