Same thing happened to me recently. I found out if you have polarized glasses you can use those to see if the glass is tempered or not. If you see diamond shapes in the glass, then they are tempered. It makes sense, when I wear my polarized lenses driving my side windows and most everyone elses has those daimonds on them. I also read you could use two polarized filters, one on either side of the glass and if you see a cross that way, just what I've read.