Heres the deal I do not have a gunsmith license but I was an Army Armament technician when I was in the military. I qualified to do complete rebuilds on every small arm in the army inventory (M9, M11, M4,SAW, mortars, shotguns, chainguns and howitzers). I was approached by the local sheriff who has his department starting to issue ARs and several people in the (very small) town I live in to clean and service their firearms which are all along the lines of what I used to work on in the military. I was only going to field strip, clean and function check. I am NOT modifying, part changing or repairing. Can I legally do this? Need a business license,etc? P.S I live in Indiana if that matters.