I've always wondered if the top on my regal is aftermarket. I seen the same top on a regal in a junkyard. The reason i think its not factory is because its not the normal vynal, its more like cloth, it also has an emblem on the dash and the side that says presidential just like the one in the junkyard, I've never taken a vynal top off of another car but when my car got broken into in high school I had to take it apart to get at the back window there was a fiberglass shell, here's some pics...