My vote is the dealer is mis-informed as usual. I know my car (2011, no CWP or heated seats) has mirrors that are heated when it is cold enough outside...
I can't find the 2012 guide but here is the '13 ordering guide where the Premium Pkge is described and there is no mention of heated mirrors as part of that package.
http://www.m3post.com/forums/showthr...dering%2Bguide