That looks great.
On the metal, if you can remove them, cut sand paper into 1"-2" strips and use a piece of wood the same width as a backing stick to keep everything even and flat. Start at around 150-220 grit to remove the old finish and scratches. If it's steel, work up to 320-400 grit to get a nice smooth finish then finish with cold blue. If aluminum, leave at a coarser grit and get you a spray on finish like cerekote, which is sold for firearms finishing and typically available in a variety of colors. The bake on finishes will be the most durable, but there are others that do not require baking that would work as well. If you can't take them off, you can tape off the wood and still pretty well do the same thing, but the bake on finishes wouldn't be an option then.