1971 Heat Shield Bracket Finish

[Sheldon S.]

All the small reinforcement brackets on the underside of the body are dip painted black and I found evidence of that on those pieces except for the two brackets that are riveted to the firewall that hold the lower edge of the heat shields. The heat shields have a black phosphate finish but what were the brackets?? Are they black phosphate, dip painted black or natural?
Thanks in advance
Sheldon