The number on mine is 2048.

The top of the barrel is marked NAVY ARMS CO.
The right side of the barrel is marked Made In Italy.
The left side of the barrel is marked .58 CALIBER XX, then there's a shield with something in it that I can't make out, with a five pointed star inside of a sunburst-like symbol over the shield. Next to that is PN with the star/sunburst over it. Then there's FINITO with the star/sunburst over it.
On a second line, there's F.A.R.A. 2048
The shield/star/sunburst is repeated on the tang.
The serial number is also stamped in the barrel channel of the stock.
The barrel has three lands and grooves of equal width.
The bore is shiney, smooth and even. The grooves are about .010 deep.
The lands havesharp edges that are slightly rounded for the first 1/8" at the muzzle.

The guy I bought it from says he bought it in 1955 and was very definite about it, but the inside of the trigger guard is stamped 1969 - whether that's a date, part number, or whatever I do not know.

Are these markings pretty much the same as yours? If so, do you know the manufacturer?