Reverse engineering plating on moly sprocket drive

I am reverse engineering a cargo plane actuator with gear systems, sprockets, and chains.

Material analysis was done on all parts. The sprocket Drive material is AMS 6520 (Chromium-Moly Alloy Steel) but plating on teeth was not identified. The metallurgical analysis report says "Black material with predominat sulfur content, but moly was not identified".

I am guessing that the plating has corrosion resistance and lubricating characteristics.

With what is known, What kind of plating process I can use that will meet these requirements?

It would make some sense that the coating was Molydenum di sulfide.It contains sulfur, is black and is used as a break in coating on some things like gears. PS, it is spray applied and baked on, sometimes over a phosphate coating for better application. IE: not plated.