Correct. Service replacement caps were chrome so that they could be installed immediately on a vehicle of any colour.
Original-equipment caps were painted body colour.
Wow, it surely is beautiful! Do you have the correct
black plastic insulator collar for the output stud? Some companies list this as "1960-up", which is wrong. There was no insulator as original equipment in '60. In '61 a rubber boot (p/n 2258 754) was supplied as factory equipment early in the model year, with a TSB advising of its availability for retrofitment, which slipped over the ring terminal on the end of the wire. The insulating collar showed up for '62 (p/n 2291 093) and replaced the previous rubber boot.