I think your engine has "had some work done" during its life...
Looks like the wiring was replaced... (not uncommon).
According to a wiring diagram I have seen based on a hobbyist's #42 on tinplate times, the wire from the lighting post may have been run from the headlight, or perhaps a dedicated run to the same terminal on the reversing switch.
The sliding shoe pick-up is proper, and the "Manufacturing Co." stamping on the reversing switch agrees with the brass plates on the end-doors.
I think it narrows down to 1917-1918.
The reversing switch should have a threaded nickel pin protruding from the tab: it threads-into the metal & fibre tab, and there is a small nut on the backside to lock it in place. The outer end protrudes just to the edge of the shell or slightly further.
Do you plan to clean / polish any of the nickel-plated bits ?