I’d be fine with a used bracket. I know I need an air pressure gauge and my tach doesn’t work so I need to see if it’s the gauge or connection I’ll have to double check to see what else I will need for gauges
Looks like its aluminum? Mine's steel. Might get lucky and find some used parts at a wrecking yard. Either that or fab up one as suggested above. Exhaust port for range/split I'm not 100% sure where it is. Might be on the knob itself.
Steering box mount? Hanger? Could just call a dealer. They should be able to pull it up and give you the proper name. Besides you never know they might actually use that style of bracket still. Probably not and price would likely make you drop the phone but you never know until you try. Besides the call is free and sooner or later you have to get something from them on a truck that old. Good luck on the truck. Btw if you get a fab shop to make one l would downplay the fact it holds the steering box on. That might put a scare into them liability wise.