I have also done the same thing for two of my cars. The Camaro insert is the same.
If you are fortunate enough to find a NOS US made pad they fit a bit better, in my humble experience.

I was wondering about that. If you took a square Impala brake pedal could you carve out the center and then install a Camaro "DISC BRAKES" medallion?

Not sure if the Camaro medallions are the same size.

Also I wonder how you could cut the rubber out with a drill press short of "burning" it out with a wood bit?

It's my new side business... producing 4-speed disc brake pedals :-)