Is it a brushed nickel? The serial number indicates it is not stainless, since the stainless guns started with CR rather than C. I have a blued gun (Mark I) that is C217XX, and I am told it was made near the end of the Bellevue operations. Detonics made a Mark II that was brushed nickel back in the company's early days. Although they weren't listed as a production model in the later years, perhaps this one was made to order. It also might have been made by an employee, or maybe even nickel plated after it left Detonics.