For a fair number of parts try personal messaging the CGN user known as winchester. I was able to get a fair number of parts to aid in the restoration of a 1886 in 45-90 I have. Replacement barrels can be had from barrel makers here in Canada or you can import via Bits N Pieces (CGN member) Green Mountain replacement barrels at a decent price. Original iron sights may take a bit of doing - replacement sights likely if you check around various gunsmiths' spare parts boxes.