I'll have to check to be sure, but I'm certain that in the Assembly Manual that th factories used show that if the truck was not equipped with a bumper factory installed, they came with a license plate mount under the left tail light, just as the AD trucks had. I may be wrong about that, I need to check the manual, when I remember where I put it! :hammering:
I do know that there is an RPO code for a rear bumper, that would generally mean thet it was installed at the factory, not the dealer.
Here's a pic of mine, with the factory style bumper and plate location.
http://rides.webshots.com/photo/2143877990092261295Fvdwnc PS, I'm inclined to think that your truck may not have had a bumper factory, it may very well been dealer installed. Especially since it didn't have the holes for the plate.
