What I believe is a Sheridan P68sc.
A friend of mine gave me this as a bag of parts and said have fun. Through google searching I found a ton of helpful information on this sight and have been able to fix it up into working condition.
It has new o-rings on the valve and a new CO2 cartridge seal. It sealed up very nicely and was able to hold a fresh cartridge for about three days until I removed the cartridge.
It was missing the plug for the magazine tube so I made a new one, as I am sure is obvious by the photos. At this time it is still bare aluminum but I can paint it black if desired.
The original black finish is in fair condition. There is some wear from the pump as would be expected but everything else is in good order. See pictures and make your own conclusions.
I am asking $120 shipped.
Enough blathering, here are some pictures