You have some good details there to start with. Also served in 1965-66, then again in 69. Could the confusion be due to doing more than one tour? Just a thought. Do you have any inclination about where you were shot down? Take a look at a map of Vietnam and see if any of the provinces catches your eye. And also, do you have any idea about where in America you were from? That information will help greatly with verification. Also if you have any inclination about how you looked/a name that is also another starting point.