Overall view of the bottom of the S-IVB stage as it sits.
At the extreme bottom of the stage, note the mount points for the main tunnel.
Also note the sections from the S-IC's cable tunnels standing upright behind
the stage; presumably, they have recently been painted.
This is S-IVB-D, the dynamic test stage. If this were a flight stage (or even
a more flight-like testing stage), I would have expected to see the cold
helium lines. However, the Model
Specification, Saturn S-IVB-D Stage reveals that each cold
helium sphere on that stage is simulated with a "dummy mass," so the stage
lacks the plumbing associated with the propellant