68 Coronet wagons (and perhaps Satellite/Belvedere wagons, too) used the same switch with mounted circuit breaker for the tailgate window. 69s are different (rocker instead of toggle) and I'm not sure about the 67 wagons. Good luck with your search.
The 68 Satellite wagon has a rocker switch just like the light and wiper switches. I could have sworn the 68 Coronet wagon we parted was the same but you are probably correct since it was several years ago when we parted it.