How Much Will Market Value Jump?

Assuming it is genuine.

Generally speaking, if Krause notes the existence of a coin but doesn't list a price (especially in the 1800's, 1900's and 2000's volumes), it usually means that the things are so rarely seen that they haven't been spotted for sale anywhere, so there's no data to base a price estimate on. It's entirely possible that every single specimen is known to be in a museum or public collection, and therefore none have ever been bought or sold.

It's difficult to estimate the value of such pieces. Supply and Demand rules apply; an incredibly scarce coin can still be pretty cheap, if nobody's ever heard of the things.

If one were to turn up at a brick-and-mortar auction house, the auctioneer would base his estimate on educated guesswork: what similar items have realised in past auctions. But in the end, it would be just a guess; the market would determine the "true value" on auction day.