I'll respond to your email address as requested, but also here as there may be others who might be interested under the heading of "knowledge not shared is knowledge lost".
The very earliest of the phaeton and roadster doors had three side curtain sockets, with the forward-most quickly deleted when it became obvious that with the door curtains in place, the amount the door could be opened was restricted by that third side curtain fastener. So, there were both two and three socket versions of the doors with a drooping valance at the top of the inside of the doors that captures the top edge of the door trim panel. Legitimate examples of the three-socket version of the doors are exceedingly rare as the known earliest surviving complete phaetons and roadsters all have the two-socket version of the doors.
A roadster recently listed on ebay had three sockets on its doors without the drooping valance and with the raised molding around the hinges, but despite the best efforts of the seller to obscure the body's origin, it is beyond question a Brookville body.