If you look closley at either of the two chassis view photos you posted above, you will notice that the pushbutton mechanism on your radio was designd to accomodate the use of nine pushbuttons. I think this could mean that there is also out there another radio model that also uses the same setup as yours. I have searched the net, but as of yet I have not been successful in my search. Should you find it, it may open up new prospects as to a donor canidate radio???
However having said that, these pushbuttons seem easily duplicated. In the pictures they look as though they are crafted or molded from white metal or soapstone. You could also cut them from Gray Marble with a tile saw.
Just thoughts going through my mind.