What you are being told is the usual way this hooks up, But the 1967 is different. In later years, a 3 wire combined NSSS+backup light switch was used and the outer 2 wires go back up to the bulkhead connectors; 1 receives 12v from the same fuse that runs the turn signals and radio and the other goes back to the rear body harness to feed power to the backup lights.
What may be confusing in 1967 is that the NSS and backup light switches were 2 separate switches on the trannie. So you may have a newer trannie and the older harness.
Was this an original auto trans car and does it have the original trannie? (You can tell as that would have a single wire switch for the NSS.) And does it have a console? Please let us know. Lacking that info....
See if you can find one of 2 wire pairs/connections:
1) Look at the bulkkhead connectors and see if you can ID connections F and H. If there are 2 purple wires going from there on the engine side then those are what should connect to the 2 outer wires on a newer 3 wire switch. (This also means the was formerly a manual trans car.)
2) If no wires go to F and H on the engine side, but there are a matching white and purple wire on the inside connections at F and H, then you can wire into those.
3) OR, you can dig around in the car to see if there is a 2 pin connection to the auto trans that drops into the tunnel (it may have been pulled up under the carpet) under the console area. If so, then let us know and we can figure out how to wire that into a newer 3 wire combined NSS and backup switch. That 'through the tunnel' harness does connect into the console light harness in some fashion if you have the console option.
And I have never seen the 1967 NSS; it may that the 3 wire combined NSS+backup switch fits into the same hole but does not work the backup part.....that requires some looking up so please answer the questions about do you have the original auto trannie or what...
BTW, I am using the wiring diagram from here:
http://www.mymopar.com/index.php?pid=27