Have you searched EBay? Started a wanted ad here on FABO? Do you have the part number and do a nationwide search of NOS parts vendors? If you start altering parts, it’s hard to go back if that fails.
All really good points. Again, I’m doing this search for a good friend and I have done a ton of work on his wagon so I have a bit of an attachment to it. The last wagon lens on eBay was over $800usd. I considered ‘63 tail lights as well.