I was looking for some knobs to use as replacements which lead me down a rabbit hole of the coolest antique radio collection I've ever encountered. Radio Guy Antiques is a slow website, unfortunately, but it's worth the hassle of waiting for the pages to load if you're into history.
I actually had, and sold, one of these. I don't think they are that rare. Even though they weren't sold directly to the public, many stores sold their display model once they were done or went out of business. I picked mine up at an estate sale and the daughter said her grandfather simply asked the owner to get him one, or at least that's what she grew up hearing.