Bill,
The differentiations are as Larry states with the Beschi complication. Italian parts= #470xxx. Krupp and Dutch =#471xxx. Beschi's are serialized in the early 470 range and are easy to spot because ICD is xxx out or not to be found. Many prefer the #471 series guns for parts they believe superior to the #470's and more experienced workmanship. I like the #470's and believe that engraving is better and truer to the classic Ithaca(patterns were changed for the 471 guns). 470 guns need be judged individually due to the ICD learning curve. Apprx. 250 of each Serial # range were made for a total of about 500+ real ICD guns.
Bob Jurewicz