[bronze 72 super]

You say Accessory Book, but what years? I deal mostly in '71-'72 and have Accessory Booklets for both years, and no mention of this option. Must be for information for earlier years. How ever Map Light Mirrors were available as an option for all '70 model year passenger cars. I have one in my El Camino. It was part as the Auxilary Lighting Group RPO NO. ZJ9. Very common years ago. Seen lots of these in cars, most common in Impalas and Caprices years ago. Don't know about other makes of G.M. but it was more that likely available as an option. And this option I'm sure was available for other years too.
Hope this helps out a bit. I still have one of these mirrors stashed away!!