Climavit is the "thermal" double paned glass which was used on the W140's. My 92 500SEL says Climavit on all 4 side windows, and I've never seen that on any other MB that I can recall.
The easy way to know if it's from a W140 is if there is a black stripe along the top edge of the window. I believe it's about 1/2" or 3/4" wide. You'll know right away by seeing it, as most regular glass is clear right up to the top edge and this looks distinctly different.
If it has this stripe, then it is from a W140. Yes, I've heard these glass pieces were $700 new from the dealer also.
Maybe try to sell them on eBay? I can't imagine there being any aftermarket glass for these cars, so some W140 owner might be interested.
As a related note, I've heard (from an MB trained tech) that you can't break this glass (when installed properly in a car door) with a regular hammer. You can only break it using the "claw" end of the hammer. Apparently a regular human being whacking at the glass with the flat end of a hammer can't get through it.
At $700 a pop, I'm certainly not going to try it on my own car
