For some reason most people towing RVs think they need a WDH. Most people towing trailers in general do not. Take a look at all the contractors towing flatbed, equipment, and dump trailers. Take a look at all the race car guys pulling big car haulers. The vast majority of them don't have a WDH.
The Superhitch on my dually is rated for 1,700 pounds of tongue weight WDH or not. I tow my flatbed with excavation equipment on it loaded up to about 14,000 pounds. It rides really well.
The main reason RVs so often need the WDH is that there is very little you can do to alter the tongue weight. There's not much movement in the furnishings and gear like there is when loading cars, tools, and equipment.
The buyer of this trailer, I'm assuming, was picking it up empty. I would think it was sold that way. So, no water, food, gear, etc. in side. He may find that when fully loaded, particularly if the fresh water tank and large storage compartments are in the front, that he will need a WDH to deal with the heavy nose weight.