Here is mine. I bought her off a high school student in Idaho. I always wondered why there was a big ass plug in the roof, just like Kemick10's in the post above me. There are 3 holes in the roof, 1 plugged, 2 I sealed when I bought it and holes in the bumper that I used for my lights. I looked up the code on a ford truck registry and it said its for the california/nevada area.
Interesting and fun information, got me looking. The codes below are slightly different from Steve83's, but are from my Ford 1990 Bronco Specification Book. His reference shows 72 as San Francisco
and my reference shows San Jose
My Bronco below (74) was ordered by the Seattle
District Sales Office. It was a custom order, although not a "special" order.