I also have an AR pistol and i'm pretty sure(but I am not a lawyer so talk to rapgood for that one) if you have it slung or in one of those custom holsters it is fine for carry, so long as your not holding it AKA brandishing.
HOWEVER I also would tell you it is NOT PRACTICAL to carry it as an OC or even CC weapon for personal protection as it is to unwieldy to be useful.
The 30rnd mag sticks out quite a ways on mine. while I love the way it feels to have a compact weapon which is also fun to shoot, it is really designed to be carried in hand which would be a NOGO for OC or CC.
If your carrying for protection use a compact pistol, save the AR/AK pistols for the range, rallies, home defense, and the back country.