I don't know when the change was made to the tops, but they are interchangeable. The only differences are to the cantrail, or drip edge, and a flat rib that was added to the later tops in the center of the top on the underside to help hold up the headliner.It may serve an other purpose I'm not sure. I believe the TRF headliner has the extra material in it for this rib. The early style cantrail was chromed steel, and the later type were aluminum.