1965 barracuda spare tire cover question

I never owned a new Barracuda, but the used ones I had used a fiberboard, similar to door cards and covered with a trunk mat. The 14 inch spare tires always stuck above the trunk floor in mine and it never looked great. I have heard rumors that there was a 14 inch spare well made or cars ordered with the 14 inch tire options, but just a rumor. I am sure others will chime in and there was a member here with a Book of Knowledge posting, it should be explained in that book. Good luck with your project!