Maybe not the help you’re looking for, but I did quite extensive work on sorting the original radio in my '63 coupe. Here is the link to one of those threads:
For reference, Mike Frank has good info on his site re. radios.
In my case, I wanted original, but also to change the polarity. No problem, my Blaupunkt was one of many that was switchable between polarity. So today, my radio sits on the shelf waiting for the car and it has two current technology speakers, uses neg ground, sounds great for its day. There are a few folks on J-L who know their way around these old radios. If you seek them, you’ll find them.