Old Coulter 13.1" Primary

Greetings, Can anyone tell me if the Coulter 13.1" mirrors made in the '80s were ever 3/4" plate glass? I recently purchased one on (fill in gap) and it wasn't the Pyrex I was expecting. Your help is much appreciated.

Thanks!

Hi Steve, I have owned 2 of the 13.1's and neither had pyrex mirrors. Greenish plate glass. The thickness was at the most 1 inch and probably as you say, 3/4 inch thick.

GG