If it's tempered, then keep it out of the dumpster. It's easy to check. I found a test on websites dedicated to home aquariums. Some aquarium owners modify them by drilling holes in the glass so they can add a sump pump. If their tank is made of tempered glass and they try to drill it, then it will shatter. So, they developed a tempered glass test.

It's pretty simple. I took my laptop from work home, found a web page that was all blue, held the screen behind the glass, put on some polarized glasses (I used the 3D glasses they give you at the movie theater), and looked through the glass at the blue screen. If you see black lines or a darkened smudge in the glass, then it's tempered. Seeing no lines means plate glass, and you can pitch it.

Try the test on your side car windows to see the lines.