anything that was "an option" would be put on any size truck the owner asked for it ... "dealer" options could be from any 3rd party, not always GM, and could be from other divisions of GM, like GMC or one of the car divisions .... and that heater control also looks like a car item, I suspect your truck was owned by a scrounge at one time, who preferred to come up with his own improvements from a wrecking yard, it's a pretty safe bet none of those 3 things were on the truck when new
Bill
