I own a RV4 '59 Burst and I own a '76 Fender Jazz. When I read your question it got me thinking, so I got out a tape measure, got my 2 basses and started measuring. The difference amounts to about a 1/2 inch in each measurement or if you took a router to the '76 and removed a 1/4 inch all the way around, you would basically have an RV4.
What I would consider a bigger question is regarding the PU placement. There is a noticeable difference between the '60 and '70 positions. They both sound great but I would recommend that you make your decision based on that rather than body size. Truth be told, I don't notice any difference in the body size when I play, what I notice is the difference in the necks and the sound.
Food for thought!