Richard, welcome, from the year you gave, Numich's firing pins are either old stock or stock they have had made, and most likely are for a Featherweight frame. The Regular frame as yours is, the firing pins are a little different.
Regular Frame firing pin.
I'm not sure what you mean by striker plate.
The two piece top tang was used until the early teens.
Picture of safety push rod installed.
Butt plates you can get reproductions at Brownell's, Vintage Gun Grips, Midway, etc. all look the same and probably from the same mold.
Good luck and any other questions, don't be shy to ask.