While browsing online checking out LTM Leica camera bodies, I came across one -- said to be a IIIa -- for sale in the U.K. that sports an unusual shutter speed dial -- see the photos. It is stepped so that part of the dial is taller than the rest of the dial -- it looks to me like the dial is of one piece, not a regular dial with something glued/screwed on top. I note that the camera has a flash sync installed on the front near the slow speed dial. My first guess was that the stepped dial was part of a sync system -- maybe some sort of lobed cam that engaged a shoe-mounted bulb flash as the dial rotated during exposure. But this body has a sync on the front -- could it have had two sync systems over the years? It's a mystery to me, but I'm willing to bet that someone here on Photrio has seen this before and will reveal the answer!
