Morris Hallowell (www.hallowellco.com) had one of these rifles in the same caliber a few years back. It didn't last long at 13K USD, and condition appeared to be similar to yours, maybe a bit better. These rifles were insanely expensive for the period in which they were introduced, costing about 1,000 Depression era US dollars. The real prize would be one in .335 Halger.

Great piece of gun making history. I don't know about the sympathetic restoration - have had a few of these done myself and still have mixed feelings. Might be best to clean it only and leave as is.