Correct Rear Leaf Spring and Hanger Finish?

Some were bare steel, which rusted in a manner of weeks, some were painted black, there is no way to tell, since springs came from different suppliers, the shakles were bare steel also. I used Eastwood Diamond Clear Satin to coat my bare metal peices, I painted my springs black. They appeared to be bare steel from the factory as I could find no trace of any paint at all.