Need help with finding an older Marlin part

I am working on my Marlin Model 2000 and I need to replace the firing pin spring P/N 420594. I would also like to replace the firing pin P/N 220599. I contacted Marlin and they said they do not have parts for these older guns. This looks like a standard bolt that Marlin used at that time. I have a manual from a Model 15YN and a lot of the parts are identical. I am thinking that this firing pin spring is a standard part used in a lot of guns. However the Model 15YN uses the same firing pin, but the spring P/N is 420994. I am guessing that it would work in my Model 2000.

Any idea on who might be able to supply these parts