Not uncommon... they don't all do it, and the ones that do, don't have it originate from the same place(s). What you need to do is try to find the offending places and put a little foam tape (weatherstripping works well) between the pieces that rattle. Some folks have gone the route of just treating all the seams between pieces just to be sure they got them all.
A telltale clue to help you find the bad spots is to look for a little "extra" dust along a seam from where the two pieces vibrate against each other.
Also, be sure all your fairing mount points are nice and tight. I've seen two nearly new B12's that had loose bolts where the fairing bracket mates to the steering yoke.