For collectors they would definitely be worth more.
For users, paying collector prices might not be worth it to most but if they are reasonable I can see people doing it.
If I lost my Carbon V recon Tanto I wouldn't see paying maybe $150.00 or so for a replacement to be too much, for example, since I've used mine for many years and know the knife well. I'd be less inclined to pay much for a Carbon V knife I did not use. If the price was around $300.00 or so I think it would be too much.
Then there are the knives that have been totally discontinued which would sell for high prices to collectors.
The Urban Shiv will sell for high prices if you can actually find one for sale. Carrying something like a Mini-Tac or Counter-Tac would usually make more sense.
The Urban Skinner would be worth more to collectors but probably isn't really better than the Safekeeper III which is the same knife, though both are discontinued.
The current Urban Pal probably cuts better than the original which was very thick for its size and chisel ground, but the older one is rare so it would cost more. It probably also would cost more if they were both made at the same time considering the all-metal construction and leather sheath.
I don't think there would be much difference between a recent pre-GSM and a post-GSM knife of the same model in the same steel, especially since they'd likely both be made in the same factory to the same specs.