I've restored about 6, the rivets are pretty easy. Hansen Rivets sells all you need, but the rivets are tubular, not split/star end, but I can live with that minor dfference on the inside of the box.
http://www.hansonrivet.com/w02.htmPut in with a hand press.
http://www.hansonrivet.com/w82a.htmI bougth a 2" throat, and have since seen a 3 head set, which is the way I would go now, as some need to use the hand clincher.
http://www.hansonrivet.com/w78.htmI've used it on a few grilles too. Expensive, but when you need it, worth it.
Actually IMHO a lot easier than many DIY tasks on thes cars (rather do this than remove and reinstall door glass and all the door guts!).
The box being competely disassembled makes blasting metal parts far easier.
And I find masking makes it real hard to get crisp edges and "dotting' tape or something else on top of the rivetes is a bit trickey, or they get painted. Looks OK, but not the same (not that anyone is ever going to see it or appreciate it, but on the bench I inspect 'em all too closely).
They are not perfect, but I'm pretty happy with my efforts. Here is a '68 I did a while ago.
I use stainless steel rivets, so not correct, but I like the fact they will not corrode.
I don't clear coat the housings.
I do paint all exposed interior metal surfaces with a cold galv grey paint, not leave them natural. A compromise for durability vs original I can live with. I also tried a light wipe of POR-15 manifold grey with a rag, two light coats, on some. And that seems to work OK too (I think the one in the photo may have used this process) . Not quite "natural" but keeps it from rusting so fast. Have used clears in the past, but found rust would get in under some, possibly just not thorough prep, but went with color that was close instead.
Thanks for confirming black on the brackets.