I expect to and would willingly pay £300 if cosmetically/structurally very good. Spring/seal etc about £40 for poor performance and I'm a happy person.
Off to surf the net now.
P.S. offered £350 for a good one of mine, by a gunsmith/shooter, not a minter. Refused 'cos it shoots so well.
It's all about opportunity/individuals. One just went for £70 on line.