ECS only lists the sensors for the front. ThE piece the OP damaged is shown as #9. It's different from the pieces on the rear bumper. The item he listed in his first link is rather close in appearance...I'm not sure how close since it looks slightly off from what I've seen in the past and what's listed in the link below.

RealOEM.com * BMW E53 X5 3.0i Park Distance Control (PDC)

To the OP, I went back an checked to see where I put those pieces, but can't seem to find them (I may have tossed them). Ill be picking up a second bumper for another project tomorrow, I'll look then to see if I can get a part number off it for you.

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