It is a Gran Premio, not the Roma. They are almost indentical, if not identical, except that the Gran Premio had the serial number stamped vertically on the right hand side of the seat lug, as it happens in this case.
Also the seat lug is different with a longer spear on the Roma and the seat stays, in the Roma, are brazed more on the side rather than directly into the lug as in the Gran Premio.
This to make the frame stiffer with a stronger rear triangle for competitive riders compared to the amateur target of the Gran Premio.
Both great framesets though.
Also the Gran Premio sports Campagnolo rear and front dropouts and was mounted with cheaper components.