And they decided on "Development by customer"
This entailed replacement models having a different part number from the originals.
A succession of different part numbers for the same component arrived, each, - probably from a different supplier or with some modification or other.
Eventually, having near enough destroyed BMWs reliability reputation, they found an acceptably reliable model and they painted them black to indicate that this was the one to have.
Your's bucks the trend.
Basically, though, they are all interchangeable.
Myke