yea, rear glass is always AS1 spec which is tempered, AS2 laminated saftey glass is windshield glass. you can check the glass label/ tag on it, on the bottom
sometimes in the middle, sometimes on the side it will say AS1 or AS2, auto manufactures have been doing this ( stamping glass information on window ) w/ window glass since as far back as 1951 that I know of, because my 1951 Chevy has every window stamped w/ glass information, and it's factory