I believe that Jeep actually changed the design of the 2012 jack to incorporate the sames elements as the "cover" used on the 2011 models. For 2011, you use the jack without the cover for the front "pinch" welds, and then use the cover for the rear of the vehicle. The new jack is designed to be used for both front and rear.
For those that rotate your own tires (as I do), you may want to invest in a seperate Pinch Weld Bracket adapter that can be used with floor jacks. I bought one from Eastwood, used it last week on the fronts with no problems. For the rears, I have an old custom made flat steel bracket with a 3/8" pin sticking out the top. It worked great on the rear lift points.
I also quickly figured out out heavy the full size spare is when lifting out of the well!
(I use the spare so I only have to have one tire off the ground at a time.)