It is a Powerlyte Powerstix frame. Unfortunately I do not have another frame to test with. However the marker was performing correctly before the valve
Yes it's doing auto response - one shot on pull and one shot on release.
I have inspected and measured the on/off pin, it's
Since they come up rarely, anywhere from $100-250, but it depends on the buyer. Start high but out obo in there and hope someone really wants it.