Вы правы. Погуглил и вот что нашёл:Сообщение от Alex65rus
http://www.173rdairborne.com/dogtag.htmNo official record of American soldiers being issued these instructions exists; the only purpose of "the notch" was to hold the blank tag in place on the embossing machine. The machine used at this time doesn't require a notch to hold he blank in place, hence, today's tags are smooth on all sides.