Why do 68 & 69 dart iginition switches have different # ground plug ins?

67Dart273 said
A multimeter would clear this up in about one minute. IF it's a ground---no switch needs a ground. It might be?? did they have a "key light" option? A quick look at the 68 service manual (Valiant) shows one pin NOT USED

View attachment 1715392557

Here's the connections from the '69 Dodge FSM.
Accessory and Starter connections have been moved.