Is this chap, as I've heard or read once, the Johnny Libs formerly of Lib's Candy? Have seen this picture from time to time in various books and articles on the Vietnam War, always wondered if he was really who I'd heard.
There appear to be two Libs named John if I read this correctly, father John ( Bob's brother) and his son Johnny ( Mike's brother)
I should elaborate a bit as to my curiosity, I saw this same photo years ago and the caption IDed the chap as being from Evansville IN. but alas I had not remembered the name until seeing it again. Link below to the source of this photo found googlefooing recently which gives a name but not hometown of soldier.
As to the M-14 seeing use in Vietnam, all I can say is that it was the weapon carried by my FIL's company. He returned stateside in '67 and retired from service after 25 years . I recall him saying much of his time was spent in Kontum province .