To my understanding it kind of is, but I think it is also almost like its own kind of licensing. I believe acro pilots have a couple different tiers of licensing that allows them a little more leeway on how low they can fly and exactly where they can fly. I'm pretty sure that's how it goes because you have to have a special type of license to perform aerobatic maneuvers close to the ground and close to people/buildings (Read: Airshows)

Again - I could be completely wrong but I think that's how it goes.