These are very good shocks, dial them firm for playing and soft for comfort. They are also rebuildable from JRI if you ever need to. I have them on both of my slings. If I wanted them I would make him a reasonable offer and you can be riding like a Cadillac.
Its pretty hard to tear up a shock unless you went off-roading with it or got into a wreck. He says not used much, but you will never know , even with a picture. His profile says he is 52, so I would think your safe.
One set of mine are the hydraulic lift and I just sent them back to JRI to check and rebuild the rear after the hydraulic actuator went bad $75.00 These here don't have the hydraulics to worry about, just like my other set. You wont be disappointed.
My Slingshot has 8500 miles on it. I had the JRI non adjustable on it at first. They were on it the 1st year. I probably put about about 4000 miles on it with those shocks. My Slingshot has never been caught in the rain. A hose has never been put on it. Only spray waxed. The clicker shocks have been set and forgot about. It is adult driven. I am not in a dusty environment. These shocks look like new because I clean the shaft, shock body, and springs. I have the DDM upgraded sway bar and end links. I also have an extra set of end links(red). I am considering the air ride for my Slingshot. I am also thinking if I will have problems from the air ride; since I will be making my suspension more complex. Better hurry before I keep them. Lol.