They're first and second generation guns- if you have blowback issues, shave 1/8" off your valve pins. It was a common problem with the earliest models.
Their value is relatively low anymore, but they're very well made. The sears and hammers did tend to wear out, though, so spares of those parts could be valuable. I think they're a bit too cheap to be real collector's guns, unfortunately. I paid around $100 for each of mine, and both are later models in excellent condition with all the bells and whistles. The single trigger frame might be a draw if you sell those- maybe as a lot, or at $40 each, if they're working well.