I'd date this mid-1950s, assuming the components are OEM. As noted, the Sport rear derailleur first appeared in late 1952 for the 1953 model year. The brake calipers appear to the Universal 39, which were reportedly last marketed in 1955. Personally, I was leaning towards Magistroni of the crankset. I also thought that the hubs appeared to be the matching Campagnolo Sport hubs.
While not proprietary, that lugset had perhaps it's widest use by Torresini, who were best known for their Torpado brand. The two names that are routinely associated with 1950s Bartali bicycles are Santamaria and Fratelli Margherita.
This is a nice sample of a classic Condorino style bicycle, outside of the repaint. However, it's not what I'd want for a rider, if that is the OP's inclination. Those single pulley Sport derailleurs have a very limited range and the pivots wear quickly, leading to very poor shifting. For me, the Sport was a classic example of Campagnolo having taken one step backwards, after having taken two steps forward with the Gran Sport.