Based on Fingers and Hawg's comments, it looks like this is one of the ASM products with a Colt barrel from 1982. There are no markings on the barrel - either under the loading lever or anywhere else - other than the address line on top and serial number on the bottom.
The give-away should have been the Italian star PN stamp on the cylinder.
Shotput: Yes, I do intend to shoot it. I've got a Euroarms replica 1851 Colt Navy, .44 cal, that I bought in Germany in the 1970s. Love shooting it, but it's starting to show its age.
Hawg (or anyone else who might know): By any chance did Colt also contract with ASM for the frames and trigger guards? That might explain the lack of foreign stamps on those parts, although it doesn't explain the missing "Colts Pat" on the frame and "44 CAL" on the TG.