65 Barracuda Headlight/Wiper switch replacement/new wiring harness/new switch

I received a brand new underdash wiring harness from Classic Ind. I got the model for electronic ignition rather than stock. I don't want to put new wire into old switches, so I want to replace the headlight switch and wiper switch. First, I can't find a replacement for the wiper switch from CI...do they exist? Second and most important, Classic shows a replacement switch with 7 terminals and an 8th on the back of the switch which is the proper year replacement for my car. However, the switch i extracted has only the 7 wire plugs with no 8th wire on the back. I'm afraid that my new wiring harness will want that 8th wire. What is the deal with the extra wire on the back of the switch?