Looks like at least an 7 1/2" barrel Abilene model. The frame is marked Riverton, NY. Asking price is $400, but this shop is mainly a military arms specialist, so they might come down quite a bit. I was thinking it would be a nice short barrel conversion candidate.

Why not a 475 or 500 Linebaugh ?????

I think I am going to go pick it up tomorrow morning. Something about it is calling me. They aren't worth a lot, but the build quality is there.

Yes, something that needs to be considered on a custom build. Even at todays prices the builder must consider it as a love of labor. Never knew a wealthy custom gunmaker.