The director shall issue, without an additional charge, upon application and payment of the registration fee, special number plates or validation decals making them distinctly different from other number plates, to any person registering a truck or combination of trucks and trailers as a farm vehicle under section 39-04-19. The director shall determine the form and size of the special number plates or validation decals and shall adopt rules governing the issuance of these special number plates or validation decals.