Actually they are not always included. Jeep keeps changing the package but my '12 has the factory towing package (500/5000) but no load levellers. When I drop my 4,000 lb (gross) travel trailer on the hitch, the 460lb tongue weight drops the back about a inch.
I am considering some Air Lifts
in the back to level the Jeep when towing even though I've never noticed an issue. Did price the load levelling shocks at one point but they are not cheap.