If it still has the part number sticker on it (from the FAQ):
67 Firebird AM/FM 986824 68 Firebird AM 7305572 68 Firebird AM/FM 7305582 67-68 F AM Die-Cast Face Plate 7298249 67-68 F AM/FM Die-Cast Face Plate 7298474 69 Firebird AM/FM 92FFP1
You don't get stereo when you use the FM converter, right? I was tempted to do that as well when I replaced my radio but the no stereo thing changed my mind.
I have an original AM/FM (mono) radio in my 69. The band change (am-fm) is done by pushing one of the black buttons that also select pre-set stations. There's no slide bar gto select am/fm. Those are found on 'wonderbar' radios often used in Corvettes etc. The stereo am/fm has chrome buttons versus black plastic, but I believe the band selection is still done by one of those buttons, not a slide bar.
There is a company that will turn your am radio into a am/fm stereo using the same shell of the am radio just replaceing the insides. The last I checked they were still doing it, just takes a while. A little less cost than the firebird central radio they are selling,
Funny you mention it i have a 70's era pioneer 8 track and it works fine , yard sale 5 bucks..LOL
I have the schematics for the AM radio. i have 2 working and one not. as far as i can tell the only thing that makes it a unique radio is the push button length.