The original poster suggested restoration, which means the Rochester carburetor.
For those who have upgraded to Carter carburetors, the finishes should be:
Cast iron throttle body - Parkerized, then painted with Carter special body paint (hint: use 60 percent gloss black).
Zinc castings (chromate like the Rochesters - see the caviat in the post above)
Aluminum castings - left natural.
Steel pieces, including screws: Carter was located across the street from Howard Crown Plating. When steel items came from the stampings shop, they were delivered to Howard Crown, and plated with the military protection du jour. Crown used white and yellow zinc, and white and yellow cad; all four finishes would be considered correct. The most common of these would be white zinc. I have new old stock Carter carburetors (later, in the early 1960's) that exhibit all four finishes. Would guess about 65~70 percent of the steel finishes would be white zinc.
Jon
