Rolling Block Help

[alfajim]

I made a reply to this last night but it appears to have flown off into the ether somewhere. It is a nice looking gun overall but I noticed somethings about it and am offering my 2cts worth.
the rear sight looks to be a rear sight from a 1879 trapdoor buckhorn 3rd or 4th version and the front sight hood also looks to be from a trapdoor as it looks identical to the one I have for my trapdoor.
Not sure what Remington but plates should look but the tang on this one looks to be a trapdoor configuration and maybe the barrel band spring?

Jim