Can you tell what makes this GT / CS one of a kind?

The story of this is unusual too, this was of course put together from a good candidate for restoration, and a donor car.... but the donor car was the unusual part. This guy is easy to talk to and he told me how this one of a kind happened to be... he was visiting family when he happened to drive past a GT/CS in the front of someones yard. He asked if it were for sale, and the old owners told him it was his if he would tow it away. It was in the front yard because the dad had given it to his son on the day of the drivers license test getting passed, but the spoiled son (c'mon, who is given one of these for passing a drivers license test?) threw a temper tantrum the size and shape of a fired brick through the windshield screaming how he didn't want this old piece of crap, he demanded a new car. Dad was dumbfounded, and reversed years of ruining his son with favoritism by punching him out, and parking the GT/CS in the front yard, and letting it rot away... hence the parts car -yours if you tow it away- availability. If I remember right, that's how the story goes.

Ford never made a convertable GT/CS, this owner wanted one bad enough to make it from a GT/CS and a donor ordinary convertable. Car guy trivia.