['ol Pinion head]

'69 & 79 GrandPrix radios were the exact same size & shape as those used in '69 & 70 LeMans & GTO's. An aftermarket somewhat stock appearing unit that will fit in a '69-72 GTO without cutting the bezel will also fit in a '69-72 GrandPrix.

For owners searching for original Delco AM-FM's for these years, the '69-72 Pontiac A-body AM-FM MONO radios had black buttons.

The '69 GP & GTO AM-FM multiplex (stereos) were near identical. The main difference is the designated '69 & 70 GrandPrix AM-FM multiplexs had outputs for two rear speakers while the Pontiac A-body only had one rear speaker. Also, '70 GrandPrix radios continued the use of chrome plated buttons, while '69-72 Pontiac A-body AM-FM MONO's & '70 "GTO" AM-FM Multiplex's had black molded buttons. For '71 & 72 model Pontiac A-body's & GP's, the top option AM-FM stereo was a one piece unit, no longer having a separate amplifier; ie, the multiplex unit.

[1969GPSJ]

Thanks, OPH!
That is pretty much what I expected. It just did not make sense that there could be a fit issue for GPs vs the A body cars. The decorative dash trim pieces I have now are both missing the divider between the push buttons and the body, and the car is a resto-mod, so I am not searching for a perfect trim piece, just one that looks good in the car. Even though I have repaired all of the obvious of any structural problems or dash flaws in the body of the dash (including some prior owner gratuitous butchering of the radio area, the radio opening is now a continuous rectangular hole, which mostly matches the unmolested dashes I have seen in the past (none of which included a "bar" between the buttons and the display area of the radio - to the best of my recollection and ability to find images on the internet).