At left is bassist Chuck Day; Ann-Margret, of course, and at right is guitarist Johnny Rivers (Remember "Secret Agent Man", "Baby I Need Your Lovin'" to name just two of his many hits).
Next to Rivers is drummer Mickey Jones, who later that year toured Europe with Bob Dylan, and was Kenny Rogers' drummer.
See: http://riversjohnny.blogspot.com/2010/01/jrs-vietnam-shows.html for additional VN tour photos.