I just noticed this now but it may have been discussed before.
Look at the photo below of a Rebel Hoth Trooper blaster. Notice the piece middle left which looks quite similar to the barrel tip of Boba Fett's ESB sidearm?
And the six hole thing behind it looks like the blocks from Boba's rifle scope.
Wow, very interseting finds. I'll need to look into this a little more.
Its also on the other side. Two of the pieces to the left of it on this side are from the Revel Visible V8 model kit
that round piece in the middle of the pic with the four screws in it looks like a part of the ROTJ stock plates
Talking with RS about the detail, that piece would be VERY SMALL to be used on the sidearm. While the shape is similar, the size seems tiny.