Your dealer must have been thinking about the Porsche factory glass top from a 2003/04. This thread is about an aftermarket glass top.
The 2003/04 factory glass top will not work on your car because a 2003/04 has a 4 bow frame and a 1997-2002 with the plastic window has a 3 bow frame.
The aftermarket glass top will work on a 1997-2002. The glass window on the aftermarket top is not as tall as the factory glass window or the plastic window so it is able to tuck down when the top is closed.
More pictures here.
http://www.renntech.org/forums/index.php?showtopic=4503