I wouldn't try to disassemble any early lever-arm shock wiothout proper tools and know-how. Some have springs and can cause physical damage to you when released. If the shocks have obviously been leaking and are crud-encrusted you'll have to have them rebuilt.
Most have fill plugs. If the arms are stuck or very stiff, you could remove the fill plug, drain the fluid and refill with a hydraulic jack oil. Bolt them in operating position to your work bench or the car frame and, after a few hours, gently try to move the arm through their range of motion. If there is not improvement, drain again and refill with a light oil like Marvel Mystery Oil.
Leave the shocks alone for a couple days then try again. If the action feels like it is improving, check fluid level, add if necessary, then let sit a couple more days. Try again, If you feel resistance and motion is good, and no leaks are evident, Tunr upside down and drain, run through the cycle a few times, let sit to drain all fluid. Add hydraulic jack oil and give them a try.
I've done this with various makes of shocks and gotten good service from some and wasted fuid on others, but with the cost of rebuilding, you may consider changing to modern tube shocks, cheap and easy.