Well, hey, look at that! I just took out my deluxe LP and looked at the book, and what did I find? I have four of the eight stills tucked in the back of it (Siobhan McKenna as Mary, Jeffrey Hunter as Christ, the sermon on the mount, Joseph with Mary riding a donkey). I totally forgot I had these!
The portfolios were sold separately along with the souvenir books in roadshow theatres back in 1961. $1 for the hardcover books, 50 cents for the softcover, and 50 cents for the portfolio of 8 photos. Studios knew how to promote films back then, and films such as KING OF KINGS were theatrical events.