That is interesting. From your photos, I can tell It's not .32 ACP. If it was, the 9MM cartridge would not enter the chamber at all. I suspect it's .30/7.65 Luger, just as the hand written note indicates. I know factories did supply guns for the Italian market in .30 Luger. I have seen a Colt Commander so chambered and marked, and I had a factory .30 Luger Hi Power. If this is one factory produced and intended for the Italian market though, I would think the chamber would be correctly marked, and not marked 9MM. As mrerick mentioned, I too would wonder if the barrel has been sleeved to create the .30 Luger chambering. Pretty neat acquisition in any case.