OK. Back to your Legnano. I erred re location of serial no. I meant 'seat tube'. Legnanos usually have a serial no. stamped into the seat tube at the very top of the tube. Not that it means anything; I have never seen a chart of serial nos such as Raleigh or Schwinn uses to date their bikes. You might want to check over the cranks and chainrings in hopes of finding a stamped date code. One other item I noticed was the lack of the classic headbadge. A high end Legnano recently sold on eBay also lacked the headbadge and was identified as a 1972 by the original owner. So at some point in time Legnano eliminated the headbadge and went with a decal version. Not sure when that took place. Perhaps another C&V member can help out with a headtube marking timeline.