I believe that Terry is referring to the cross section of the shank of the pedals and not the shape of the pedal pads, which were round.
The lower-mounted pedals and brackets are early '33 with two different pedal configurations. The earliest pedals use carryover '32 pedal pads which are attached to the top of the pedals with thin nuts and thin lock washers. There were two versions of the brake pedal of that earliest type, the first one with a welded-on tab for the brake light switch and the other with the forged-in tab. The next version of the '33 pedals still used the lower bracket but the pedal pad studs were enlarged and screwed directly into the threaded tops of the pedals.
I don't know when the higher bracket was adopted in '33, but both pedals continued to have shanks with oval cross sections like those shown in your photos. Based on what I've encountered, the clutch pedal with the girder-type cross section of the shank is likely from a second supplier and started to be used during either the tail end of the '33 model year or near the beginning of the '34 model year. Both types of clutch pedal shank cross sections seem to have been used throughout the rest of the '34 model year. There was a '34 brake pedal with a girder type cross section as well, but they are only infrequently encountered.
