Honestly I wouldn't get my hope up. The receiver has been drilled and tapped for standard scope bases. The barrel at best has been cut way down, assuming it's not aftermarket. The stock is clearly aftermarket, and it looks pretty short ahead of the action. And it only has the single shot adapter, not a repeater. I agree the scope is work $700+, but I'd only put the rifle itself closer to $700.
I agree. Definitely not original, in any way imaginable. Barrel has definitely been cut way down, reblued, restocked with a nice piece of wood. The op can argue, that it would cost more to recreate, but the rifle as a whole is what it is. Probably still worth a little more than your $700 quote. I'd say around $900, and the scope being worth a good $700.00. That would bring the value up to around $1,600.00 IMHO..