I wouldn't trust anything from a salvage yard unless you are really familiar with shocks.
I read about rebuilding the stock shocks by drilling a hole to drain them about 1/4" from the bottom of the shock body, draining it, welding or JB welding a nut over the hole, refilling with fluid, then tightening a short bolt into the hole. Might not hurt to try, and could be a fun project.
Camelman