Here in central Colorado every pawn shop has a couple of T/C's, generally .50 caliber, priced at $250-$300. As to what they would actually take for them, I don't know, was just never interested enough to enter into bargaining. But those are the .50's, I think .54's probably bring more money as they never built so may of the "Big Boar" versions and they have been long discontinued.
As to T/C's "lifetime warentee", that holds only IF they have the parts. Things like locks, triggers, guards, sights and such as will interchange with current production Hawkens you can get. Barrels, breechplugs, tangs, and stocks were specific to that long discontinued model and lots of luck gettign those parts.