i wouldnt assume anything. look up reese.com, or the hidden hitch. im sure you can look up a hitch for the trucks. what all are you looking to tow? im sure there will be more telling you to buy the full size because you are goign to tow. The truth all depends on what you plan on doign wiht it. just remember you will tow more than you plan. Look at the gvrw of the trucks and what your towing.
As for the coolers, you can add aftermarket ones and you should be able to tell just by opening the hood.as for the hitch, mopar has its own so I highly doubt that the hidden hitch was factor.
something else to look at is your space. will a full size fit in your garage, or where you park the truck. would it be easier to get around in a smaller vehicle where you live?
Me personaly, I would go with the full size because I tend to tow towards the gross.