i too have a 2012 reg cab. the window rattles are able to be corrected literally in about a minute. Lower the window so that about 2 inches of glass is above the door - you will notice an inside window retainer across the top of the door. This is the interior glass retainer channel and is u-shaped. If you move the glass, you will see the rattle is caused by this having too much play. Lower the glass all the way. Get some foam rubber (black) and trim a piece about 8 in long, 1/2 inch high and about 1/4 in wide. Just place this in the channel, closest to the rear of he door. Do the same, with a slightly thinner piece, closest to the front of the door. The rattles are now gone.