The original black paint on RD carbs was fairly fuel proof and lasted well. However, it certainly peels eventually. The OE paint was almost a gloss and, painted over everything, including brass screws and springs, although I think the choke lever mechanism was not painted. I would think the paint might have been 2k, but I am guessing. Painted carbs are possibly the most difficult thing to do well I think.
Cheers
5port