Just curious, what you say it will not fit? I put a 79 bobcat full metal hatch on my 72 that I had years ago. It bolted on just fine. And other than having the holes for Mercury, it was the same.
Maybe it is because the gasket? The early cars, the gasket was glued in where the later ones had to slip over the pinch weld. The glass hatch had a special gasket. He might need to modify the lip to get it to fit.
That is the only think I can think of. In my opinion, the rest of the pieces should bolt in.