Date and location.
From what I've read/remembered, Girardengo had work outsourced to a prison in Alessandria, including the time when such frames (two badges) were made; which said reading/memory claims was 1962-64.

But as well, can you find out the frame angles?
I have one and the seat tube is 75.<something> and the headtube is 71.<something>, a curious combination as each is somewhat extreme on opposite ends of the scale.