It's an out side covering to shield the wood and they are pot metal. I had a set, but I let them go with the basket case 29 3 window coupe I had. I believe they are 29 specific, and I am not sure if they are being reproduced, but if anyone has them it would be the filling station. They have a ton of old chevy stuff. I like the sedan delivery concept you are shooting for. I have made two of them from chevy sedans.
John