I don't know. But I've been a Ham since I was a kid in 1982 and I know many hams that were licensed in the early 60's. I've always heard it was someone's "fist" that was unique. However most operators since the early 80's use what is known as a "keyer" and a set of paddles. One paddle make the dit (dot) and the other makes the Dah (dash). The keyer makes perfect spacing for each letter and therefore makes you sound less unique but better and easier to copy. Also using an electronic keyer allows you to send much faster (>60wpm in some cases) than a straight key like you see in old movies.