Long Step spare tire mount

[78stepside]

Hello everyone. I'm new to the site. I recently bought a '78 C30 long bed step side. It used to be a Boston mosquito control truck. I'm actually looking for a spare tire mount or the information on where to get one. I know that the short is different from the long. I found a couple of different ones from suppliers but they look nothing like the originals. Any help or information would be super helpful.

Thanks,

Dave