My '37 Chevy truck project came without the original bumpers. A fellow stovebolter gave me a bumper that was resting outside in the dirt. Turned out it had a slight bend in it. I took the rusty crusty bumper to Royal Plating in Tucson, AZ (
https://www.royalplating.com/). They heated the bumper since it is spring steel, straightened it, and then polished and plated it. It came back looking beautiful. They said they had the proper pattern for it.
I know you are a long way from Tucson but perhaps you can find a similar shop nearer you.
Kent