[bwright657]

Are you closing the door with the glass up or down? My coupe rattles if the window is down but is OK if the window is up. Keeping the glass from rattling on frameless doors is extremely tough and gets more difficult as the car ages. I've given up on keeping my 99 Miata glass rattle free and just make sure it doesn't leak.

My first guess would be that either one of the seals that is supposed to keep pressure on the glass is loosening up due to age. First I would just try putting some seal dressing (I use Nextzett on my cars) on all the seals before you start going down the rabbit hole of replacing seals. After that start looking for gaps between the seal and the glass and try and apply pressure in that area by hand or with some painters tape to see if stabilizing the glass there solves the rattle.