Service replacement rear springs were often painted black with a part number stenciled on the top surface. Have pictures but away from them at the moment Coil springs typically paint black also for service examples. While, as Bob described, heat treated items such as spindles, center links and so on were wax or oiled and look allot like assembly line items
Thanks Jeff. My leaf springs that came in my car were service replacement leafs as far as I can tell and they were painted black, but were most likely repainted during the last restoration and there was no sign of the stencil that I could find or part number stamp, but will be media blasting them tomorrow and will find out soon enough. So far I like the graphite coating and have been experimenting with some different procedures. I have a bunch of parts waiting in the cue, spindles & various steering parts that require a natural finish. I will post the results when I am done. The current procedure call for the following steps.
Dry Media Blasting
followed by Vapour Blasting
Heat Seasoning
Dry Graphite coating application
Boesheild Application when graphite has dried
0000 Steel wool wipe down for final step and finished look