They never made the .30Carbine in stainless steel. KMR-1 is a generic part number. It should be followed by a caliber designation like KMR-1-44 for .44Mag. No KMR-1-30's exist. Only the MR-1-30, which is blued.
Do you have a .30Carbine Blackhawk that appears to be stainless? If so, it's probably nickel or hard chrome plated.