The body didn't change but be cautious to frame changes at the mounting points. With the new 3.6 coming out and changing safety standards. Frames do change more than one may think.
Call the jeep dealership and ask them, most dealerships will sell aftermarket bumpers at a huge premium of sales increase so they will have the most recent information. They will know if the 2011 and 2012 front frame horns are the same.
I've read where Jeep relocated a vacuum canister behind the bumper on the '12 and many aftermarket bumpers will require a bracket to relocate this canister.