Reply to "Reverse switch location"

Question:  I am finally reinstalling my back up switch after years of it sitting in the engine bay.  The ZF cover is not threaded and the stock switch (which does work when the lights are on and depressed sufficiently) threads are smaller than the hole.  On the early cars, was there a nut put inside the case to secure the switch along with a nut on the outside to lock it in place?  Any insight would be appreciated.  thanks