Not a great picture but it may help a bit.
Picture of a NOS C9AF 2100. Should be one or two out in the trailer btu apparently have not taken any nice clear pictures
Zinc dichromate or dye depending on the metal that makes up the part
Looks like throttle shaft, butterflys and linkage on the drivers side. Any of the wire clip would be P&O. Believe the spring is dyed either a red, blue or green based on the application
Screws that hole the carb together and attach the choke to the main body.
Don't recall if the throttle adjustment is zinc or zinc dichromate but the accelerator pump linkage appears to be P&O
Choke plate, choke shaft
Linkage from choke shaft to choke (arms also) and also choke body, choke cap retainer and heater hose bracket. Clips would be P& O
I would suggest that if your going to get some plating done you gather a bunch of parts for your car, duplicates and multiples since often there is a minimum charge to do the plating so it may be the same price if your doing a handful or coffee can full especially (like most places today
they are using the tumble/basket method of plating
One issue with restorers is that they often sent everything out and have it plated all the same color so you may be trying to not have that happen by doing it yourself
Also the condition of the metal will effect the final look of the part. Plating will not hide imperfections but in stead make them more visible
Hope this helps