S.C. Code Ann. § 56-3-1810
The number of plates that may be issued to members of the National Guard by the department shall equal the number of private passenger motor vehicles registered in such person's name in this State; provided, however, that the total number of such plates issued to any one person shall not exceed three. The department shall issue such plates for a particular private passenger motor vehicle registered in that person's name and such plates may only be transferred to another vehicle upon compliance with the provisions of Section 56-3-1830.