115V outlets are standard on the Sahara and Rubi models (and thus the special edition vehicles that start from those models like the Arctic, Altitude, COD, Moab, 10A, ect)...
However, it was, and is, available on a couple of Sport models, and it does seem to be attached to heated seats.
During the middle of the 2012 model year, Jeep offered Katzkin leather as a factory installed option on all three models. When a Sport was equipped with factory Katzkins, it automatically included heated seats and the 115V outlet.
For the 2013 Freedom Edition (which is based on a Sport), partial leather seats became a standard, and heated seats became an option. When you include heated seats on a 2013 Freedom Edition, that also includes the 115V converter.
So basically, all Sahara's and Rubi's have it, regardless of leather or heated seats. But if you manage to get one on a Sport, they are usually attached to heated seats with leather of some sort, which is rare to find on a factory Sport.