Interesting that the bikes listed on the CR dating page that start with a zero are from the fifties apparently. And that flat fork crown looks the part.
http://www.classicrendezvous.com/Ita...al_numbers.htm
A couple things of note. The lack of both the elongated cutout in the seat cluster and oil fittings on the BB shell and head tube. Is there anything stamped on the bottom of the BB shell? Also, what bottom bracket is in there? And have you determined what the dropout hanger takes?
Cool frame.