COOL, I have my fingers crossed!

Very early Masi Speciale frequently didn't have serial #'s OR a frame size stamp. Later ones had a frame size stamp generally. The head badges disappeared in 1968 according to Bob. Have you looked at your hubs closely are they 3 pieces (two spoke flanges pressed on to the center barrel) ? They could be early Gran Sport which would fit if the bike is older than you think.

vjp