This just fell into my hands this morning and I'd like to know more about it.
The previous owner has had it reconditioned and repainted, I think only the shifters and front wheel are original, but they look to be gran sport "open C" and the QR has the dogbone nut. Which puts it in the 50s I think, maybe you campyphiles can confirm...
The head badge is long gone but has vertical holes spaced 34mm apart
The previous owner bought it used in the 60s he thinks, also that it used to be a track bike, also that it was "magnesium" ... So for whatever that's worth, maybe there was some tubing I don't know about?
Serial number is on the drive side seat tube near the top: 7715 with another incomprehensible punch before it.