Well....there may or may not have been a universal treatment of these items. They can look credible multiple ways, provided they have no body color overspray on them!
Here’s what I did with my ‘76 at the recent Big Re-Paint:
Hood Hold-Down Bar
The original bar on my ‘76, as well as a spare bar I purchased — I don’t know what year car it came off — were factory finished in silver and yellow cadmium, which I had duplicated in clear and yellow zinc.
Both bars showed the same original finishes: the straight bar and the big center spring were plated in silver cadmium while the jogged bar ends and miscellaneous hardware were plated in yellow cadmium. The first three photos below, of my ‘76 in August 1983, illustrate this distribution of finishes. By 2012, the finishes were really bad, but you can still see, where the plastic end bushing has been removed, the yellow cadmium of the jogged bar end, fourth photo.
I don’t have a good photo of the bar ends today, but the fifth and sixth photos should give you the idea.
Wiper Motor Arms (in the Plenum)
Yes, rust-and-overspray is the common appearance. Although I’ve seen examples with what might have originally been silver cadmium, as Mike S. notes above, most of the late wiper motor arms I’ve seen might have been originally galvanized. If so, they were plated thinly, as rust is common. The seventh photo shows some of the original finish left on my ‘76’s arms. That rectangular connecting bar was, however, silver cadmium plated, and done much better than the arms. I thought that clear zinc would “over-bling” these arms, so I had them powder coated a flat, dull, light gray, and they now look like a clean version of the original — no photo available. But, to be clear, I used powder coating to approximate the original appearance: I believe the original finish was some sort plating or galvanizing.
Regards,
Steve