The claim is that "originally" there were only four people in the limo when Kennedy was shot.
Note the picture carefully. GOV Connelly and the agent on the passenger side look a lot alike. And some camera angles, plus the clear partition (which looks almost like a second windshield) between the front and middle seats, can easily obscure there being three rows of seats.
JFK_limousine_cc_img.jpg (1440×907) (thenation.com)
