Idaho Code § 49-407
Pursuant to rules of the department, any person who is the owner of a motor vehicle with any model year up to and through 1974 which is registered under section 49-402(1), Idaho Code, or section 49-434(1), Idaho Code, may display on the rear of the vehicle an authentic Idaho plate manufactured with a painted or embossed year matching the model year of the vehicle. The provisions of this section shall not apply to any vehicle with a registered maximum gross weight over twenty-six thousand (26,000) pounds.
In addition to the regular registration fees required in sections 49-402(1), and 49-434(1), Idaho Code, the applicant shall pay the initial program fee and the annual program fee specified in section 49-402, Idaho Code. All revenues from the initial program fee and the annual program fee shall be deposited in the state highway account.
Idaho Code § 49-407