I did see some going in the "thousands" range when I went to Nashville last year for the big Civil War show. I was looking more at books than guns since the guns were all beyond my meagre budget. An engraved Henry with provenance will go for about $20k.
Dunno about this one. Missing stock to me isn't a big deal as it can be replaced even if it means buying a walnut blank and having it fitted (easier than you think). It should be American Walnut and not European (yes, there's a difference in grain) for authenticity. The buttplate is the tricky part.
Vigilantibus et non dormientibus jura subveniunt. Molon Labe!