Well, I finally picked up the 2012 BMW tailbag. The 2010-2011 model is on the right, and the 2012 is on the left.
The first thing I noticed is that the bottom underside section is significantly different than the tail bag for the earlier model, which I suppose is due to the difference between the tail sections. I was under the impression that the passenger seat was the same on all the models, but you can see the seat impression for the 2012 version is wider, and although it's not apparent in the photo, it's also a little deeper. I installed it on my bike and it "seems" to grip the seat a little better than the older version, but I haven't ridden with it yet so I don't know if it will creep forward. The only other difference is BMW logo on the handle...an imprint logo instead of an embossed logo.
Anyway, if you have a 2012 model and decide to get the OEM tailbag, make sure you get the correct version as shown on the right.