So you got an aftermarket piece? Usually the MB part numbers are like 124-240-06-18 (this is the transmisson mount part number, BTW).
Maybe the radiator in your V8 is different from these of the inline 6. I see that part as an integarla part of the radiator of my 1991 300E. Then my 1987 300TD does not even have that part on the radiator.