Spectre rear shocks

1100 Spectre rear shocks. Are these air pressure only or is there a small spring inside them? They seem to be stiff, like sort of bound up, anyone have issues with them ever?

I've not had any issues with mine so far (1983) but as far as I know they do have a spring inside them because i let all the air out of mine by accident (don't ask) and it didn't sag/bottom out. It may be an idea to dismantle them as far as possible (Outer sheath if you can) and maybe clean up/Re-lube the pistons. It may be the shaft is covered in dirt/grime.