[Arran]

Mike;
  If the 39-6 is like many of the smaller wooden table radios that I have had the celluloid dial lens had a flange that was either tacked or stapled onto the inside of the cabinet. On sets that have both a metal escutcheon and a celluloid lens the lens was often riveted around the inside perimeter of the escutcheon, with hollow tube rivets, and did not have a flange. Not doubt that this was a cost saving move on Philco's part, to the not too observant both the 1938 and 39 models would look alike, but Philco could eliminate some extra parts and labor by eliminating the escutcheon in favor of the finished opening.
Regards
Arran