Yes please post a pic. I've never seen one for a 72-80 truck including for the ones that my family bought new which I still have one. The more that I think about I've probably owned more like around 50 of these. Heck I have 5 right now.
I've had the Equipment Identification some under the hood and some in the glove box lid. Have also seen the option tag under the cowl plate.
They can be found in several locations: under the floor mat, under the insulation padding that is under the seat, behind the dash, and the most bazar to me has been in the transmission crossmember. One of the 2 that I have for my LRE has dealer installed undercoating on it, luckily on the backside only.
Here's one from my '79 4x4 Roundup pkg. truck:
