Re: What is the correct weight specs
Unless you're misquoting or my eyes are screwed up (very possible), both towing capacities are capable of moving you pop-up, fail to see the problem. If your question is why the difference, possibly the pick up wasn't intended to tow in the stock arrangement.
Also, if you're dropping 2", yo might want to consider some sort of helper if you're towing it a lot or over long distances.
Chewing on asphalt and drinking dinosaur wine