Yep, those were tube days, and I think I can still remember most of the schematic diagrams I had to draw for the exam. I was 15 years old when I took the test, my CW speed was way higher than most, and I was able to copy 20 WPM with ease, which was big help when I entered the U.S. Navy. When I was preparing for the exam I copied 5-letter code groups that were sent out nightly from WWV, which I was fully prepared to do during the exam. Instead, they sent written sentences, which to me were easier. In the Navy we had to pass what was known as the I-N-T test, (.. -. -) sent at 5 WPM--it was almost boring. If you could handle that, then the drill instructor sent you to the advanced testing center, where they determined if you were smart enough to go to radio school. Only about 5 percent of those sent to the advanced area were accepted, regardless of their ability. The rest were assigned to other billets, gunners mates, deck apes, cooks, and any other job slots that needed warm bodies. It took me another year to get into radio school--they sent me to Underwater Swimmers School in Key West, Florida first.
BTW: I took the online exam at the posted link and only scored 37-percent. Minimum required to pass was 70-percent.