Copper variants of Iron decoration blocks, should have unique textures.

The copper bars, chains, & maybe the lanterns too (I dont think the torches though), should each have a slightly different designs to the iron variants, in the same way that different door variants do.
For example making the copper chains chunkier or rounder, or making the copper bars thinner or more ornate. I think in the most extreme version of this, the copper lantern could be given a different model to make it stand out next to the regular lantern.