They are pigtails for options that your car apparently doesn't have. Orange is the 12V feed for the dome/courtesy light circuit. It also feeds the clock (which is probably what that plug is for). The gray wire is the illumination circuit for instrument lights. Again, that probably feeds the illumination bulb in the clock.

 

Back when your 69 was new, it was easier for GM to produce generic wiring looms for each product line. Not like todays cars where each car has a unique wiring harness. You're certainly brave tackling the wiring behind the dash of a 69.