The assembly manual shows two lights in the console of a 68 Cutlass, which accounts for the gray (and black?) wires in that branch of the harness. There are also a white and an orange wire - what are those for?

 

Thinking back a bit, and without a manual in front of me, wouldn't one set be for the lights that come on when the doors open, and one be for the interior light, triggered when the console door was opened?

 

The console wiring diagram is in the Instrument Panel chapter in your Chassis Service Manual. The PIM (Assembly Manual) is not going to give you wiring diagrams.

White is the ground leg of the courtesy lights. It is connected to the pin switches in the door jambs, just like the dome light.
Orange is the 12V feed for the courtesy lights. It is hot all the time
Grey is the illumination feed circuit that powers the instrument illumination lights. It feeds the bulb under the shift indicator in the console
Black is ground for the shift indicator and console glove box lights.