My painter is pretty sure the headlight mechanicals/carriers are supposed to be black, so he painted them black. Before I assemble can someone confirm? Also what is the correct color for the faded plastic headlight surround? And do we have a rattlecan brand and color we suggest?

I've only seen grey.
I've soaked the headlight surrounds in bleach water and gotten them pretty clean but if you want a brighter white, use some rattle can plastic paint.

914Rubber sells rattle cans for the headlight surrounds they claim was color matched to the original gray. I used it and it looks good to me.

Here’s a shot of my unrestored original, removed by me from a 70 six:
Click to view attachment

The headlight carrier was a primer grey color; very basic. I used a rattle can zinc spray years ago that was pretty much the same. So Mark is quite correct on both responses.

Always grey unless someone changed the color.

I have a couple NOS headlight brackets and they are flat gray, like Dave said; cold galvanizing zinc paint is very similar.

You should be able to get Duplicolor plastic paint for the white surrounds. Just clean the plastic really, really good first