Kentuckian: I went to the same show. Did you also go to the museum across the street?
Interestingly, on one of the "used cars for sale" tables, I found something labeled as an "N scale brass tank car kit". It was actually a very old, and rather crude, car I built, probably about 40 years ago. The old house was burgled 10 or 12 years ago, and they got a bunch of "abandoned" railroad stuff, items I left behind when we move to our new place, at the other end of the lot. None of it was worth keeping, so I left it behind. Some of it shows up, at nearly every show, so it was either sold of piecemeal, or has been traded around.
I probably wouldn't have paid much attention to an old, tarnished, brass tank car, except that t was lettered for my fictional mining companies fuel-hauling subsidiary. If you ever see an MORX tank car, it's probably mine! I left them brass-colored rather than painting them black because black alphabet decals and dry transfers were easier to find. I could get them from the office supply store.
NO, I didn't buy it back. I did describe the construction to the dealer, if anyone else is interested in it.