The tax imposed by this Article is payable by any dealer who actually or constructively possesses an unauthorized substance in this State upon which the tax has not been paid, as evidenced by a stamp. The tax is payable within 48 hours after the dealer acquires actual or constructive possession of a non-tax-paid unauthorized substance, exclusive of Saturdays, Sundays, and legal holidays of this State, in which case the tax is payable on the next working day. Upon payment of the tax, the dealer shall permanently affix the appropriate stamps to the unauthorized substance. Once the tax due on an unauthorized substance has been paid, no additional tax is due under this Article even though the unauthorized substance may be handled by other dealers. (1989, c. 772, s. 1; 1995, c. 340, s. 1; 1997-292, s. 1.)