DEG Inquiry 31778 provides feedback that masking back side of bumpers with radars is NOT INCLUDED.
“After reviewing your concern, masking of the back side of Bumper Cover would be Not Included.”
In addition, any material cost for masking and cleaning is NOT INCLUDED.
Mercedes Benz provides an example in Service Information “si9800p0029a Painting bumpers with radar sensors”.
“To avoid paint residue, mask off the inside of the bumper in the area of the short-range radar sensors before painting. The masking must be removed from the inner side after the painting process. All other residue on the inner side must be removed using a suitable adhesive cleaner or silicone remover.”