The pictures below show the differences between the various Model A and the later 1932-34 Model B & Model 40/46 rear brake camshaft operating levers.
All three of these levers in the pic below are LH levers. The Model A levers stand upright relative to the camshaft, whereas the 1932-34 levers hang down relative to the shaft center.
Pictured below left to right is an A-2236-AR used on 1928 Model A's with the early single rear brake system, an A-2236-B used on 1929-31 Model A's, and a B-2236 used on 1932-34 Model B & 40/46.
The pic above shows the similarity between the early 1928 A-2236-AR LH lever on the left and the 1932-34 B-2236 LH lever shown on the right.
The 1928 lever has more of a slight 'S' shape compared to a 1932-34 lever which has a straighter lever. A 1928 lever can be twisted slightly to approximate a 1932-34 lever, and vice-versa.
The pic above shows the differences between the typical 1929 A-2235-B RH lever on the left and the 1930-31 A-2235-C RH lever shown on the right.
The -C suffix lever on the right is shaped slightly different at the top in order to position the brake rod farther outboard for added clearance to the rear shock absorber adjusting needle. This change was implemented in April 1930 according to the Indianapolis Branch Service Letters.
Most lever arms are forge-marked with an 'L' or and 'R' either on the edge of the arm or on the end where pinned to the camshaft. Additionally, many are also forge-marked with the part number.
Though the lever arms are either a Left Hand or a Right Hand, the backing plates and camshafts are common side-to-side. After an arm is pinned to the shaft, the entire backing plate, shaft, and lever arm assembly becomes either a LH or a RH assembly.
To determine if an assembly is a LH or RH, hold the plate in vehicle position with the lever arm also in vehicle-installed position and note the direction of the kerf in the clevis end of the arm. With the clevis pin in place, the service brake rod should be aimed slightly inboard towards the brake cross shaft assembly at the frame center crossmember, not outboard away from the vehicle frame and cross shaft.
After the plate assembly is identified as either LH or RH, the proper handed emergency brake mounting plate and linkage can be assembled.
Additionally, the parking (emergency) brake rod lever arms are also handed, LH or RH. The parking brake actuating lever arms are attached to their shafts with a clamping bolt and washer, and are indexed to the shaft with a woodruff key in the slot.