Acciaio is Italian for steel. Acier is French.

Ponte Zanano is a tiny village that is less than 2 km from Beretta's main operations.

It was very common for Italian makers to source the barrels from many different countries. This was true of Beretta as well.

There is an Antonio Belleri on GunsAmerica.
http://www.gunsamerica.com/976612579/Guns/Shotguns/Saiga-Shotguns/Shotguns/Antonio_Belleri.htm

Here are the Italian date codes:


Pete