For those who’re within the U.S., all real bills can have a watermark of the person whose portrait is about the bill. They’ll even have a security thread embedded in the paper that glows beneath ultraviolet gentle. Some trade dollar fakes have an used rim- they struck the coin 'disc' https://knoxhsaip.bloguetechno.com/a-review-of-copyright-usd-for-sale-69810865