Under a charge of possessing a vehicle or component part, the vehicle identification number or component part number of which is defaced, altered, or tampered with, it shall be a complete defense that the accused at the time of such possession had in the accused's possession a certificate of title from the officer whose duty it is to register vehicles and component parts in the state in which the vehicle or component part is registered, showing good and sufficient reason why numbers are defaced, changed, or tampered with, the original vehicle identification number or component part number, and the ownership of the vehicle or component part.
Iowa Code § 321.93