I need some help in trying to date a Legnano frame. No serial numbers can be found, only the stamped 50 on the seat lug and fork tube which corresponds to the frame size. It has the Columbus Tubi Rinforzati Garantiti sticker that I believe would indicate late 60s early 70s. There are two huge oval cutouts in the bb shell. The dropouts are drilled. What is confusing is that it has brazed on down tube shifters, and two small round nipples with a hole in them for the underside bb shell cable guides (cable kinkers). Kind of a mixed up puppy it seems. Thanks in advance.
Dennis Young
Hotaka, Japan