Well spotted - I wasn't looking at the inside.
On the exterior there are no panel gaps, so it looks like the Model isn't made up of loads of separate parts - which would explain why the Body is all one colour.
That's a shame because it means it's not so useful for what I want - which is testing colour combinations beyond the standard 2 colour split - and $75 is a bit much to find out wether I would still need to spend many hours working with it before I could do what I want.
Ah well, back to the Photoshop for now.