Idler,
The bracket went through numerous changes. The earliest version used clamps to attach to the foot boards. The outboard ends of the 7/8 diameter tube were lopped off at a 45 degree angle. The next version, still in late 1925, the ends of the tubes are cut square and the joggle in the tube is more abrupt (tighter radius). Then in 1926 the joggles moved outward, and the end of the tube were trapped, with a single bolt piercing the center (as shown in the picture of my foot rest brackets). There may have been more changes over the years, those are just the ones I am aware of. The bends in the tubing all lie on one plane. the only vertical offset is in the bracket that connects the cross tube to the frame.
It seems the same foot board casting was used in either case, drilled for the clamp only when being provided as spares for an earlier model.
Doug