This chapter does not apply to a person who purchases fewer than five nonrepairable motor vehicles or salvage motor vehicles from a salvage vehicle dealer, an insurance company or salvage pool operator in a casual sale at auction, except that:
(1) the board shall adopt rules as necessary to regulate casual sales by salvage vehicle dealers, insurance companies, or salvage pool operators and to enforce this section; and
(2) a salvage vehicle dealer, insurance company, or salvage pool operator who sells a motor vehicle in a casual sale shall comply with those rules and Subchapter E, Chapter 501, Transportation Code.