Increasing Tongue Weight on Nissan NV3500 (or in general)

If the NV3500 is anything like the HD pickups out there, that 870# is simply the max tongue weight for the hitch receiver. People frequently replace their hitche receivers on these pickups with higher rated ones.

Maybe I missed it, but is there no mention of a WDH versus non-WDH rating? Is the 870# for a non-WDH? If so, they usually can carry much more when used with a WDH.