CD was a Brighton suffix.
Do you know if your car was Riviera blue or the lighter Azure blue?
You can see the original rear lights were the plastic lensed 3" types with built in reflectors, although the lenses were absent. I prefer the earlier glass lensed lights, think they suit the cars vintage better. Lee Turnham from the IOCGB wouldn't accept that this car had them, he said to me that Isettas were never fitted with the plastic lenses until later. He said they must have been retrofitted. Well that's possible I suppose, after all it had a few other mods, including the reversing lights added either side of the rear numberplate.
However under close inspection I could find no holes in the bodywork where the separate reflectors would have screwed into the shell if the car had originally had the earlier lights, and I highly doubt a past owner would have gone to trouble and expense of welding any holes up.