[Drazil]

"Waffenmeister" has decent looking repro buttplate and front barrel band (and spring).

 

[Drazil]

is there a good source to show you how the assembly goes together?

The Numerich catalog has a pretty good exploded view. Not sure if it's printable, but I found it online. Can't remember where my hardcopy is, but if I find it I will try and post.