I did get a rock chip back in 2000 on the Glenn, short gravel area and a mini-truck flying in the other direction threw a bunch of gravel up. Never had a problem with big rigs, there are strict laws governing driving with cracked windshields in AK and semi drivers don't want to have damage any more than you do. If you watch an oncoming big rig up there, they for the most part, are driving slower than on hard pavement and they will slow down even more as you approach and move as far right as possible.
But, you asked about chips from your own rig, the lower portion is susceptible to chips and sometimes it is inevitable and cannot be avoided. I have seen lots of trailers with aluminium diamond plate covering the lower two to three feet of the skin. Twice I have seen holes caused by rocks stuck between the dual rear wheels that caused real damage. One was a hole about 2 or 3 inches in an aluminum mudflap and the other a slightly larger hole in the diamond plate on the trailer it's self.
I would bet that excessive speed was responsible for both.
So my practice is slow down, pull over as far as safe and smile or wave at a trucker or driver that does the same.