The made in Italy rumor well never die, it's on the internet and everything on the net is fact, right?
Val Forgett and Lou Imperato supplied parts to Colt. These parts included rough castings and semi-worked parts acquired from both American and Italian subcontractors as well as in-house fabrication. So yes, some of these parts were fabricated in Italy to Colts detailed specifications.
There is a Colt document, a 120 page "Summary of Operations" that specifies every part of the manufacturing process for the cap and ball revolvers. Machining, fitting, polishing, bluing, color case hardening, roll engraving and on and on, was done right here in the USA.
That's how Sam did it back in the day, he used subcontractors, and he even used imported parts, heaven forbid.