All you know from those weights is that you added #640 to the truck.
That's not the trailers actual tongue weight however.
As was said, you will need to get the weights without the WD and compare to your unloaded truck weights.
What's the trucks GVWR? Since you are sitting at #6880 loaded with the WD installed, you could be okay on that part anyway? If it tows okay and the front end does not feel "light" while steering, leave it alone.. If it feels light up front, you can tighten up the tension on the WD to put more weight up front.
Mitch