I guess the 40-50 dollar knives have more collectable/older dates?
I don’t think the rust will have done any great damage to these knives,
Sometimes the back springs have been known to break (over hardened?)
They have the nickname ‘nail breakers’
I think 20 bucks isn’t a bad price for a ‘new old stock’ knife
You could probably find one over here cheaper but then you have to add in the P&P
Go on get yourself one as a project