You could just find a good mechanic to do a general once over of the car. They can check all the normal items just as well as someone specific to these trucks. As far as any of the "nuances" about the syty's, you'd just have to start asking around probably...maybe some other locals owners in your area.
Even the shop in my area that used to see these trucks often, hasn't seen one in about 8-10 years he said. He mostly see's GN's now.