That was pretty common back then. The original owner of my Camaro was 18 when he bought it, as was his best friend, who bought one as well. His mother signed for the car and was listed on the original title. And, because she was the one listed, and had not moved in 50 years,(thank goodness, St. Louis) I was able to track her down through a title search. The hard part was getting her to give me her son's phone #.
At a show in St. Louis, where I was able to reunite the owner with the car, one of his friends told me "Tony drove the cr-p out of that car". I guess that is why he dropped a valve at 2000 miles.
And, the most interesting part, the oriignal owner swears the car came with aluminum heads. This on a '69 Yenko Camaro.