Find a new dealer if you need them to set the pressure. There aren't any trucks that I've ever seen that would be optimum at exactly the same all around. It is common for tire places to set them at the same pressure unless they have another reason to make them different. The normal empty case is the front is higher since the front weighs more than the empty beds.
As others have noted, it's more common to either have tires at maximum or set at the amount required by the load covered. Picking a random number is for their convenience. If this is a DRW, that means the rears will almost always be a different pressure than the front.