State vehicle inspection, tire specific

Every state's laws are different. However, you can safely put "P" tires on in place of "LT" tires provided you do not exceed the tire's maximum load capacity. Your state may or may not agree. Most state inspections are quite rudimentary and when I lived in states that had inspections, they only looked at whether or not the tires had legal depth of tread on them, if they looked at the tires at all.