The 89 XR7 molding is discontinued. It was a 2 piece unit that sucked. So Ford updated the design with a one peice molding for the later years. Thing is you have to remove the window to install the new molding. I bought one a few months ago, they are about $90. (!) I don't remember the part number, but given some time I could probably find it. Just ask for the molding for a 96 Cougar.
I also know where there is one in a junkyard in a newer cougar that is in perfect condition (new design). I'm sure you can find them around. Trouble is going to be getting the window and molding out in one piece as they are glued in with Urethane which is some super tough crap.