"I hold in my hand the hatchet used by George Washington to chop down the cherry tree. Over the years, the handle had rotted and was replaced with a new one, and later on the head rusted and was replaced. But it still occupies the same space in the universe."
Ask if you were to replace a receptacle, would AFCI protection now be required. Then ask if it was, say, a high-mounted clock receptacle, and you decided to replace it with a switched wall sconce, would an AFCI need to be added. Now, ask if the threaded holes were stripped and you replaced the box with another one, would an AFCI be needed.
An outlet is not specifically the box (some fluorescent lights are hard-wired, but are still an outlet), nor is the receptacle itself the outlet. The outlet is really the hole in the wall where the wires are accessible. You did not install or create a new outlet.