Stop in for a cup of coffee

You know....Not to start something but I need my memory refreshed. In 1972 I turned 18. 6 months prior to that I registered for the Selected Service but there was no draft by this time because Viet Nam was slowing down. When did VN war officially end. I question this because Nathan Philips the Native American with the drum in the news this week is a year younger than me and he claims to be a Viet Nam vet. How can this be?