(a) The grazing of livestock, where established prior to the date of legislation which designates a wilderness unit, may be permitted to continue subject to part 29 of this subchapter and in accordance with special provisions which may be prescribed for individual units. Numbers of permitted livestock will not be more liberal than those utilizing a wilderness prior to establishment and may be more restrictive.

(b) The Director may permit, subject to such conditions as he deems necessary, the maintenance, reconstruction or relocation of only those livestock management improvements and structures which existed within a wilderness unit when it was incorporated into the National Wilderness Preservation System.