Protection for a design under this chapter shall be available notwithstanding the employment in the design of subject matter excluded from protection under section 1302 if the design is a substantial revision, adaptation, or rearrangement of such subject matter. Such protection shall be independent of any subsisting protection in subject matter employed in the design, and shall not be construed as securing any right to subject matter excluded from protection under this chapter or as extending any subsisting protection under this chapter.