Spoke flanges would have been black parkerised, as per all the main case and through studs........nuts washers and bolts all cadmium plated. I had a go with a parkerising kit, which sort of worked, but i painted the parts over this with Matt black paint just for a bit more durability. It turns out that parkerising similar to Gun barrel blueing is only a surface treatment that should be lightly coated in oil......the matt surface holding the oil film better than a smooth surface. My thoughts are that the folk who would truly remember what is correct on these early bikes are no longer with us, and that is why the correct info is hard to find.