Either could "pull" it but you will be over GVWR. Payload will be your limiting factor. A 6500lbs dry fiver will weigh 8k+ loaded. Average 20% minimum of that on the pin would be 1600lbs. Figure in another 150lbs for the weight of the hitch and you've exceeded the payload available for either of those trucks before even adding passengers. Only the regular cab long box model may have enough payload.
People do it all the time, and it will likely handle it ok, but you will exceed ratings. Only way to know for sure is to load up the fiver and get it weighed, including the pin weight. Load the truck up and weigh it too to see how much payload you have remaining. If pin is less than payload remaining you're good to go (assuming you're under axle ratings too)
