Where can you get a firing pin for a Western field 12 gauge model 15k?

I can't find a listing for the Western Field Mod 15k. The Mod 15 is a Mossberg Mod 80, the 15A is a Mossberg 83, and the 150 is a Mossberg 183k but all of these are .410 bore, not 12 ga. Mossberg did make most of the different models sold by Western Field, so by looking through the different diagrams of appropriate Mossberg shotguns you may be able to identify the correct model. With that information, GUNPARTSCORP.com or other parts warehouses may be able to supply the correct firing pin.