Attachment 20996
Here is my old light after splitting (for the second time before binning).
The outer shell/lens is brittle red plastic which has a 'letterbox' aperture in it for the clear reverse light. This red plastic has no cracks, not even hairline ones. This is fused with the clear plastic on the outside surface which is covered in spiderweb fissures culminating in a stress crack across the reverse light aperture. Whatever has affected this is coming from the outside (such as car polish or UV light) I think.
The inner workings are plastichrome and these also have their own clear plastic fresnels lenses across them. The LEDs do not shine outwards, they are mounted 90˚ in rows pointing down or up and get shone out 45˚ to the red lens.
The question has been asked in the past if there are orange indicator LEDs present in the inner lights even though not in use. There are not, but there is room for a PCB if they wanted them or maybe they have them on USA models? Where the PCB would go is just a metal strip to stop the light leaking from adjascent segments.