Dodge didn't increase their pay load and GVWR until the DEF equipped models in 2013. The 2012 has the same weight limitations as the 2011.
I didn't want to start out more 1000lbs in the hole, the camper will not get any lighter, but will get heavier as time goes by.
I have no doubt the 2012 will handle the camper, but I try to stay within GVWR or maybe a little over if possible.
I would not like my truck without bags, they don't do anything as far as leveling, but do make it more stable. I can really tell the difference if I forget to pump the bags up, Stable loads are a must also.