It depends on year & wheel type.
There were black oxide 25mm ones for the steelies & 39mm for alloys (late MYs 74-76),
... and silver zinc plated 39mm for the alloys (Pedrini, Mahle 4-lug "baby-gas-burners" & Fuchs 2L), & IIRC they were in 25mm for the early MY steelies too (PM Pat Garvey on what were on his 72's steel wheels when new). If you have an old grody set, then I understand that you can send them to Eric Shea/PMB to get plated with "the next set" of silver calipers he does, or go to a local plater.
The black caps didn't come in until 74 MY IIRC, when they started using the black plastic center caps on the "star" mag-look steelies on your car in the initial pix above. Although those wheels were available in 73 MY, cuz my 73 2L had the infamous dealer swap-out" of the Fuchs 2L alloy for a steel spare (read "dealer stolen").
There's a good Wheels & Tires nailed topic over in O&H which covers most of the MY wheel & tire set-ups, although you'll have to trudge thru a lot of posts on stuff from long winded folks like me!
It also has a link to rfoulds excellent resto of silver painted steel wheels on his 74's star mag-look wheels, which would work the same on resto'ing the earlier steel wheels - if you decide to go that way. That technique - minus the black on the rear/back-side - would also work on the Pedrini alloys, although the prep & prime would need to be modified for aluminum alloy (rather than steel).
BTW - if you decide to go the Pedrini alloy route (several are FS on CL in the PNW right now), & want to restore them yourself - rather than send them to Weideman or Al Reed, then look for the Alloy Wheel resto kits at BavAuto, MBZ & P-car suppliers, which have the putty (for nicks & rash), alloy primer & silver paint in them.
Cheers!
Tom
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