Back to your original question, Dawna, the rear valve stems have a cap that you don't need to remove to check or add air. You will need a dual truck type tire chuck.
Milton Dual Chuck Truck Tire Gauge | Air Chucks + Gauges | Northern Tool + Equipment
One side is used to check the inner tire, (push the chuck on the inner valve stem), the other side is used to check the outer tire (place the chuck over the outer valve stem and pull towards you).
Easier than it sounds.
If you rotate the tires (or get them rotated), be sure they put both caps on the rear tires and they should be aligned together when remounted on the truck. It's a pain to remove them once they are back on the truck. The fronts are just like any toher car/light truck.
Hope this helps.
Juan