Um... I'm afraid you are all right about true air shocks, HOWEVER stock "air shocks" simply pump air into the damping oil in your shock. There is actually a spring in the canister, so you technically have a coil over shock with somewhat of an air assist. If you pump air into the shock you are pumping air into the damping oil. It effectively stiffens the shock so you can't bottom out, but limits your shock stroke and wheel travel so you have a bumpy ride overall. They're also only good for around 10,000 miles and designed to carry 180-200 lbs effectively.
A true air suspensions replaces the spring with a air spring commonly called an air bag. The air spring absorbs the energy from a bump or dip (swing arm movement) and a good one has separate chambers for damping or dispersing that energy, using deflective discs and oil. The damping is important... it's what keeps you from rebounding or "pogoing" after hitting a bump or dip. A good system should also allow you to adjust for preload using an onboard air compressor, so you can make adjustments for added baggage weight or changing road conditions while you are riding and should never allow you to raise the bike above stock height as this can cause speed wobbles. An Air suspension can actually increase your bike's wheel travel and improve your ride quality regardless of weight or road conditions. If you decide to upgrade, look for a good quality brand too. As with any bike part.... quality is important, you only have two wheels so everything should be precise.
