I'm not an expert, but I think it's a late 50's to late 60's. If some ask's the seller to look at the face of the seat lug for a serial number we may know more. Could be a Specialissima, Team bike or a Record. It might even have a piece of broom handle stuffed into the sterer tube.
These are before the cast in "B" on the seat stay caps, lugs and fork crowns.
Jim McCoin
Fremont Ca.