For what it’s worth I put a Paragon cover on my 87 Ram 50. I use the truck to haul engine and transmissions etc and having one that folds up out of the way when I need to haul stuff is nice and it comes out easily if I need to. I’ve had it for 3 years now and am still happy with it.
Your truck is older like mine so it probably isn’t listed. Chances are that there is something out there that uses the same size bed (I ended up getting one for a Ranger).
There are a couple of pictures of it here.
87 Ram 50 Engine Swap - Page 6