Subjective tastes count a lot in this area. Tradition calls for blackened barrels, ie rust blued, color case hardened action, blued furniture (trigger guard, top lever, forend iron) and oil finished stock.

My preference is for the barrels to be the only black (well dark charcoal grey) part of a gun, all the other metal to be French Grey.

Stocks I do with this method: www.linseedoilfinish.com because it combines the protection of varnish with the surface feel and look of linseed oil.