My guess is that without a WDH, the limits are 620 lbs. of tongue weight and a maximum of 3,500 pounds for the camper.
With a WDH, you can exceed the 620 lbs. of tongue weight and go up to 5,000 pounds for the camper.
Which sounds like you shouldn't need a WDH with this hw277.
Now, the tough decision- lots of people start in a pop-up and move on after a season or two (lots don't, of course). If you buy this tow vehicle, will you be able to change to a hard-sided TT in the future? Will you want to? You don't have to answer- just something to think about.