they are just a cover up. as reference, here are the CCC ones:
CCC apron
i had one on my '59 back in the mid-80's. the biggest issue with them is it bumps the profile out and the fenders do not align then. luckily i had CCC fenders at the time and could set the holes to bump the fenders out too.
i was hoping there was a pic of the back of my car on their site to see it, but i can't find one. i will see if i have any old shots at home. i was shocked enough to see my car on their site at all considering i built it in '84 and haven't seen it since '86. it is the light blue (Plymoth Grabber Blue) one at the bottom right...
