(a) No provision of this Part shall be deemed to prohibit or require the removal of any land use and development, including any structure, lawfully in existence on August 20, 1977.

(b) The development restrictions in section 661.6 of this Part shall not be deemed to require a variance for the repair, restoration or rebuilding, in whole or in part, of any structure or facility lawfully in existence, although such repair, restoration or rebuilding activities may be subject to the permit requirements of this Part; provided, no such repair, restoration, or rebuilding shall increase any existing non-compliance with the provisions of that section.