It sounds like quibbling, but there’s an important point to be made here. The kid didn’t “build” anything - he took the plastic cover off a manufactured commercially-produced clock and put the electronic guts into a pencil case. It’s important because it belies the official narrative that he was so excited about “inventing” a clock that he couldn’t wait to show it to his teachers. He obviously did it to be provocative.
Allegedly this is a kit that was once commonly sold by Radio Shack. Different than merely removing the casing from an existing clock.
Since this kit dates back to the mid-80s if not the 70s, it is possible that he either purchased a deadstock (old) kit someplace or even purchased such a project that was already constructed.
TSA would not look favorably on such a clock if you tried to board a plane with it. And who plugs a homemade clock into the wall (when it already has battery backup) in English class?