This door handle has a shorter shaft than the sedan door handles, and has a stamped steel, flat baseplate unlike the curved cast baseplate on the sedan handles. It has the "spear point" design introduced in 1930.
I will bring this with me to the Durant meet in Grand Junction next week.
Two handles for comparison in the photo above: the roadster handle with the shorter shaft and flat stamped baseplate is on the right.
As an aside; the curved flange will fit either right or left on the door reveal line, but only had one locking handle. This was on the right hand side of the car for the USA. The theory was that you lock the car on the driver's side from inside the car(by moving the handle forward), then slide across the seat to the passenger side, exit the car and lock the handle with a key from the outside. The thinking was that people shouldn't exit the car on the driver's side and potentially step into traffic and suffer a horrible fate!