I have one of those 70 Holley/Autolite manual choke carbs disassembled on the shelf.
I bought it NOS, but ran it on a car for years so it's not much help anymore as far as identifying plating types goes sorry to say.
Some of the original small pieces are of different construction than what is currently serviced by Holley though.
You'll have to replate those, but others you could buy new.
However, you might as well replate everything since it would all be covered by the minimum charge.
Cad plating is very expensive these days due to ever increasing environmental regs, but zinc not as much.
The yellow chromate is an additional process, a conversion coating to give it the gold hue on either type of initial plating.
All I can say is carefully inspect each small part for traces of original finish after spray cleaning with carb cleaner.
I don't think any of those parts would have been cadmium plated because it's never been cheap.
I had a bunch of small parts cadmium plated in the early 80's, they called it barrel plating, and the minimum was $100 for whatever fit in.
I'd hate to think what it would cost now.
My money's on some silver zinc and some yellow zinc parts.
I'm sure any number of people on here will chime in with pics of their concours or NOS carbs.