I have picked the butplates up at Brownell's(plastic type) I think it might be bake-lite material. They also have the crescent type buteplates out of pot-metal that has to be trimmed and shaped and drilled. Put alittle finish on the white metal and color it up like ya need.
Yea James, the carrier is the same item that Wisners has. Vintage Grips has the buttplates.
I couldn't find any correct repro buttplates at Brownells? They only carry post WWII era repros. I think Numrich may also have them, if they can get the order right! The M53 is the one for your 1892.