I used to just go ahead and make those simple pins as it would take less time than trying to chase one down.
FYI, I tried to take mine apart just so I would know what I was dealing with, but I had a heckuva time, and finally had to bend the firing pin to get it out. It looks like they intended that the plug at the back of the slide come out to replace the firing pin, which would likely mar the slide. That is really bad design. I trimmed off the top of the firing pin back of the notch to get it back in (my gun is a collector, not a shooter) and it works OK. I think to do it right, I would make a two piece firing pin like the Colt M1903. In fact, as I look at it, I think I might try a Colt firing pin and spring and adjust as necessary. I don't feel like tearing down a Colt to check, though, and I don't have a spare firing pin.