Jack -- You bet. Here are some photos that might help -- these show how the bed looks on all 3804's, and how your truck would have looked, coming out of the factory. Also, it was fixed to the frame -- no hoist mechanism.
Anything beyond this configuration (as on your truck) was added at some point after it left the factory. Unless you have some documentation, it will be very hard to say for sure if this was a dealer add on or a post-sale upfit that the truck owner did at some point. Your add-ons look professionally done and not farm shop "agri-engineered."
There might be some literature floating around out there for that company. There were a lot of companies, most regional, that offered up-fits like that.