Judging by the shape of the quarter, when you buy a replacement quarter or a repair panel convertible and Supreme use the same part. Inners are all the same from what I can look up at say Fusiks or other vendors. I don't even need the whole part, basically plan on using what I need near the wheel well and butt welding it in. The inners have a small area on both sides and they actually sell patch panels that should work out. BTW, I bought the same rotisserie as you did. Did you have to extend the arms to reach the body mounts in the front of the car like I had to?
On my 66 the inner wheel wells are not the same. The convertible one is flat on the top so the top can sit down all the way. Maybe this is different on the 68 and up but I don't know that answer.
My front arms bolt right to the inner mounts under the cowl, no extensions.
On the '68-'72 A body convertibles the top of the rear wheel wells are flat also so the top lowers all the way. I have heard, but have no proof, that on the assembly line they used a large hammer to flatten the wheel wells on the assembly line. Might be an myth though...