Pictured above are two variations in the 1932 Model B steering column ignition lock assemblies.
The unit on the left has a brass "Off-On" switch plate, whereas the assembly on the right has a zinc plate.
Also note that the assembly on the left has the hole plug cover in place in the left hand side of the casting. The hole was used for the starter switch pull cable on the Model B. Late Model Bs and all V8s used a different starter switch and plugged the hole.