Yes any standard lower can be attached to any standard upper. That's the beauty of the ar. Be careful. If you attach a short barreled upper made for an ar pistol to a standard rifle lower you have just made a short barreled rifle.
The average life of an AR-15 barrel is about 20,000 rounds. Let's generously assume that the average new shooter goes to the range once a month and fires 100 rounds through their rifle per session. At that pace, it would take about 16 years to wear out that barrel.