"Terne is used to coat sheet steel to inhibit corrosion. It is one of the cheapest alloys suitable for this, and the tin content is kept at a minimum while still adhering to a hot-dipped iron sheet, to minimize the cost."
I guess that this was more cost effective then galvanizing! I found a company in Illinois and one in England. I'll see what I can come up with! Thanks Dan for your knowledge and help!
But regarding the J-hook, that one might have been natural! I need evidence from an unrestored car.