Reverse switch?

OK, am I missing something here? I bought a '69 Dart GT 'vert with a 340 and 904 auto transmission a little while ago. I unintentionally found out it it would try to start in gear. I checked the neutral safety switch which turns out to be a single wire unit. It's not even wired up. I look in the FSM and see it should be a 3 prong with a violet and white wire going to it. As I start digging into this I find a switch with the violet and white wires mounted to the shifter under the console. It kinda looks factory.I dont see that switch in the FSM. Is it correct? What should I have? Why no wire at the trans?