67 GMC

My '87 has no lock button in the rear hatch but I can push inside with my finger to unlatch the mechanism. The part new is like $100 which seems outrageous. I saw on another forum that a poster wrote that this is a GM part originally (love AMC) and that certain 80's GM trucks had this same mechanism. Does anyone know what years and what trucks? Can't see it being a tail gate but maybe a Blazer lifter gate or something like that?

I can go to a pick and pull but then you need a key for the lock button anyway which they don't ever keep. If I need to pay for the old part and take to a locksmith to make a key, I might as well buy a new one. Hoping a GM part would be cheaper and easier to find.
Jeep part number is: 83510179