Political correctness to my mind is usually more about awareness and courtesy than it is an egregious mindset. For example, to me, 'jews harp' and 'scotch broom' stem from a denigrating thought. There are lots of others, of course.
I think 'jaw harp' is descriptive and far more apt. (Unless one wants to say 'juice' harp- I seem to recall there is a certain amount of uncontrolled production of head sap.):)