S.D. Codified Laws § 22-25-14.1
It is a defense to any prosecution under §§ 22-25-13 and 22-25-14 if the defendant shows that the slot machine is an antique slot machine and was not operated for gambling purposes while in the defendant's possession. For the purposes of this section, a slot machine shall be conclusively presumed an antique slot machine if it is twenty-five or more years old. Whenever such defense is offered, no slot machine seized from any defendant may be destroyed or otherwise altered until after a final court determination including review upon appeal, if any, that such defense is not applicable. If the defense is applicable, any such slot machine shall be returned pursuant to provisions of law providing for the return of property. It is the purpose of this section to protect the collection and restoration of antique slot machines not presently utilized for gambling purposes because of their esthetic interest and importance in South Dakota history.
SDCL 22-25-14.1