As long as you don't know all the parameters, it's very difficult to compare two photographs. One is a 5 minute exposure, the other taken with a tv-camera and photographed off some monitor, if I understand correctly. Maybe that camera had some low-light amplification stuff and the photo was also enhanced etc. So you can't say, the S-IVB is brighter in one than on the other photograph.

Regarding Clementine: Much smaller and less shiny than a CSM.

Harald