In the hi-tech environment, following the philosophy of "make it simple enough for an engineer to understand, and you'll have no problem", plating was referred to by its color, silver (or clear) zinc, gold zinc, black zinc. The same applied to cad plating, although cad plating was not commonly used in the aerospace world This terminology was used by almost all the companies in Silicon Valley during the 60's on.
If you download the "Mustang Hardware Spreadsheet 67-68", and scan down the FIN column (you can sort by that column as well), finish code "-S36", is for gold zinc. This will give you the hardware items. As to parts, Ford used the gold zinc finish in many electrical applications (red colored plating was for special torquing). Electrical items you encounted would be the basis for questions. Exceptions are normal.
Jim