No. The 70-72 have a different shape, thickness, and contour locations. They also have a hard plastic backing which is integral with the seat release mechanism.
73 and up, as stated above, use a completely different construction and design. They have a soft back, are thinner, and I believe wider up at the shoulder.
Using the foam might mean using the 70 to 72 cover, and it is cut out on the back, so you cant easily cover it.
It might FIT, but probably not fit WELL. You could possibly use an electric carving knife and try to make it better.
Grant