Is what makes a "market" - seller has a thing, buyer with money to pay wants to buy it - between them to sort out a final number - is only between them - what they know or do not know, etc. Nobody else can "set a price". A "buyer" with no money (or not enough money) might be just "kicking tires". A seller with exorbitant price might be just "testing the waters" - does not really want to sell it. So it goes for 100 year old stuff.
Within the past year I paid a good amount of dollars for a particular Mauser rifle that I am sure was 10% of that, or less, at SIR, about 40 years ago. Did not buy one then. They have not made any more. I wanted one and decided that I could afford that price. So I bought it ... From posts that I have since seen on CGN, I think even the seller was surprised that it went at his asking price - what he knew, what I think I know, etc. all came into play, I think. I believe that I got a "good deal", so did he believe that. But, in the end, I have that rifle that I wanted. Because it completes a "pairing". "All matching" to the last little part, both an Infantry Long Rifle 1909 Argentine and an Argentine 1909 Cavalry Carbine - both in 7.65 x 53 - or whatever you choose to name that cartridge - 7.65 Mauser, 7.65 Argentine, 7.65 Belgian, and so on... Satisfied buyer; satisfied seller - how it is supposed to be.