Also,just in case you are stopped, wreck, or they decide to search for some reason ... print out a copy of the law with the section numbers, fold it up and put it in the lock box with the pistol ..
Preferably, print it directly from the US govt. website so the little tag line shows at the bottom of the printed page where you got it from. Having a copy of a law with me has saved me hassles with Barney Fife types before.
Also, politeness and "sir" goes a long way.
…. Just my .02
Keep smiling ... it'll just make 'em wonder what you're up to...