NC tint stuff:
North Carolina Window Tint Law - TintCenter.com
Although the DMV has some fine print that suggests '32% light transmission will pass Inspection'.
And, one can cop a Doc's scrip for exceptions, eg light sensitive eyes, etc., and get a darker tint...
Back at the Getting Pulled Over Ranch, my experience is that cops can pull one over for any moving, or equipment code violation, or suspicion of being impaired.
Being pulled over for speeding/other code violation, and then the cop wants to see your windows rolled up is a legal wiggle that a good lawyer may get one out of, jam-wise, after the fact, as in court. But, they do have the cop deal going, and in my 50+ years of driving experience, I have found it difficult/ineffective to play the armchair barrister card on the side of the road.
YMMV...GL, mD