Is a Dart C&B revolver a collectable gun? -
There are folks (some on this forum) myself included, that have an interest in the older repros and the 60s and 70s is when there were a lot pf players in C&B business.
There are plenty folks that would be interested in a Dart C&B revolver for it's part in history and it's novelty since there are a lot less of them out there then Piettas and Ubertis.
That is not to say a Dart revolver is especially valuable or that one should expect much if any premium for it if trying to sell one, but the fact that it's a less common specimen would get some folks attention.
Then there are also folks who would have little interest, because they specifically want something common and normal like everyone else and may even wring there hands over the availability of spare parts etc.
So I personally agree that a Dart C&B revolver is "collectable" but more like the way sea shells or river stones are collectable than any expectation of cashing in on a fortune.