[DavidG]

It was part of the door skin stamping, not applied.

Actually there were three different door skins. In addition to the difference around the hinges, the earliest version had a drooped lip on the inside like a Model A roadster door. This was soon eliminated as the drooped lip made installing the door trim panel difficult because of the location of the '32 inside door handles. This change took place before the change around the hinges. The photos below show a drooped-lip and the later straight-lip doors.

The change in the lip is cited in the book, but I did not include a photo (and should have).