Appears it was an option to have full rear bumper in '28-'29 if a sidemount spare was fitted. Service bulletin for June & July '29 show full bumper with luggage rack & 'rack & trunk fitted.
But from Aug '29 Ford Canada offered a 'Sport Roadster' which had a full rear bumper & sidemount spare fitted from factory,If that is not good enough , some US Sport Roadsters' were also marketed in California & displayed at San Fran. Auto Show in Oct. '29.