(a) It is not necessary for the State to negate any exemption or exception in this chapter in any complaint, information, indictment or other pleading or in any trial, hearing or other proceeding under this chapter. The burden of going forward with the evidence to establish any exemption or exception is upon the person claiming it.
(b) In the absence of proof that a person is the duly authorized holder of an appropriate registration or order form issued under this chapter, such person is presumed not to be the holder of the registration or form. The burden of proof is upon the person to rebut the presumption.
(c) No liability is imposed by this chapter upon any authorized state, county or municipal officer engaged in the lawful performance of the officer's duties.