I found this in a box in the basement, it is all brass Autolock patented Jan.23 1912, I would say used on 1914 to 1916 funny thing is you could beat this lock with a small screw driver Cheers Colin
With the key removed, the inside of the KW switch base is locked onto the rear of the tumbler. Probably used mostly on 1913 and 1914's. There is a steel cover version for the '15 and '16. This is one I have on my '14.
The innards of the switch base mounted to the coil box is not the same as the standard switch. The locking KW switch base is needed to make that Autolock cover functional.
Ken in Texas
Thanks Ken this was on a 1915 switch Dad picked up at a swap meet for 2.00 according to the note he left in the box. cheers Colin