Flight Control Rods Plating

the rods were painted with the insides coated with boiled linseed oil, the only plating was the hardware, which at that time was silver cad.

New name to this group - I'm in process of doing a full restoration of my 415C.  Does anyone know the plating requirements for the flight control rods and links?  I can do the chemical checks per AC43-4B to figure out what it was, but it would be good to know if anyone knows offhand before I start brewing potions per the guidance.