I have a Buck Mark I purchased from Sportsman's Warehouse in 1998. I would like to have a backup firing pin on hand. I cannot find a source of the old style firing pin. I picked one up on ebay but the owners listed it wrong as it was the new style firing pin. Not sure on the year which the change was made but believe I have the old style.
I think you are on the right track with Ebay, maybe try Gun Broker also. I always ask for detailed pictures and some measurements with caliper. Most people selling have no clue, so you have to know what you are looking for. If they won't send those details, then I just move on. You will probably need to do lots of searching, but eventually one will come up. The other option is have one made. I am waiting for a smith to make some ivory sights. He told me if I wanted some made, he would do but would be 1 year wait. Sometimes you are at their mercy and that's the only option.
I checked both of my go to sources and they’re out of stock. Midwest Gun Works at least said the old style fits all Buck Marks manufactured before 2000. https://www.midwestgunworks.com/page/mgwi/prod/B5152657 Numrich Arms may find more in the future. https://www.gunpartscorp.com/gun- manufacturer/browning/auto-pistols-brown/buckmark
