Neither it was natural aluminum The rear alternator bracket , not sure what your referring too there.....
Sorry, the bracket on the "top ear" of the alt. The larger bracket on top holding the a/c compessor i always see painted, not thats it's right.
The arm was natural , the top bracket was a semi gloss/not quite gloss. I'm no "restoration" guy just was never my thing, but I do have probably 50 of those brackets and to be honest I've got some that are more glossy and others that are all but flat, theys no telling...
Arm was not natural it was gray phosphate plating. Cast iron paint will work in a pinch. The upper AC bracket is painted black semi gloss.