The steel adjustment bracket, or the "holding" aluminum mount? I painted my steel bracket with a zinc primer and then cleared coated it because that color was a great match for the plated coil bracket. Everything I've seen indicated they were similarly plated.
Burnish it with a propane torch after its beadblasted that will darken it and close the pores will look new
I used Eastwood Alumablast. I bead blasted a few and they look like crap. You need to do something to them. I knew that Krylon Dull aluminum used to say for decorative purposes only and not meant to be durable. Does it still say that?