Probably going to need a rebuild, so not worth much more than any other 97 that needs rebuilding? I'd consider it to be a good quality core.
Bob
This is a good point. Regardless as to how it is advertised, it would be prudent to go through it and replace the gaskets at the least. I would not pay, say $300-400 for a "NOS" Stromberg 97 or the like. I've seen some on epay for that. First off, you are paying for someone's word, and second, who gives a rat's behind whether it was actually mounted on a car or not (providing you could prove it)?
Then, there is the issue of how it was stored. Could be the throttle shaft is stuck, I've undone these, but patience is the key; otherwise it is more money spent on the rebuild. There's also the chance the power valve is stuck, or the idle jets, etc. These can be removed, but if you goof, there goes a $300-400 core. You would want to remove these to make sure some bug didn't expire, or pack dirt into a passage that will cause you grief. Improper storage could cause the castings to be corroded and pitted. Big whoop if it is NOS but looks like the average used/abused core.
A fellow club member once had me advertise on the 'net for a '53 air cleaner. I had several pop up for $30-50 +shipping. All at once he hears about a "NOS" air cleaner from a vender. Turkey paid $150 +shipping for it. I am, of course expecting some pristine item. It was faded, dinged, pitted, decals wore off in spots, and otherwise rather ratty. I guess for him the idea of telling everyone that his beat up/crusty air cleaner was NOS was worth the extra coin.