What did the factory use?

I have been using a product called safest rust remover on the suspension parts. Basically I wire wheel 30 layers of crud, rust and such off the controls arms and stuff....wash them with soapy water , rinse then dump them in a bucket with the product and a submersible pump and let it go. it is bio friendly, doesnt attack paint or rubber just rust.......

So here is my question, why am I pulling shiny, metal, completely rust free arms out of the bucket (Not that I'm complaining mind you)

What did the factory finish on these pieces consist of?