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
Yeah, Italian Masis didn't have serial numbers right through the 70's,
AFAIK, unike their US counterparts. The headbadges persisted past '68 - maybe to 1970.
The BB shells on Specials were originally solid, I believe, giving way to a three-slot design sometime in the late 60's (maybe 1967). This was followed by a six-port design (seen on both late Specials and early GC's). The four-port bottom bracket apparently starts to show up in '71, at which point they are exclusively on GC's, and would definitely
not have had headbadges. Having said that, there are apparently a number of different BB shell perforation configurations during this transition from the Special to the GC. The combination of the four-port bottom bracket and metal headbadge would seem to be something of a
non sequitor (and not indicative of an early Special or Speciale Corsa,
AFAIK.)
We will need pics, as usual. Do the lugs have cutouts?