[jumpsoffrock]

The boxes are made of fiberglass and if you look at the inside it looks like it was semi-exposed fiberglass with some kind of clear coat. Replicating that might be a but difficult, and simply painting over that with black/whatever paint does not look factory at all. I painted mine with flat black paint to try and preserve the fiberglass--I did not expect a factory finish--but I was less than enthused by the result. If I EVER wanted a correct-ish restoration now I know what NOT to do.

Pictures don't do justice but I can snap some pics of a factory box inside and out, so you can see what the inside looks like after almost no exposure for 50 years. I assume that's what the outside looked like new but I could be completely wrong.