The r4 compressor was a GM Unit,Mercedes does not make this,not only that many brands were being made in Mexico,and yes Mercedes out sources from a number of countries,so the compressor is re-boxed and sold to you for 3x the money.
These compressors are weak,expected life 5years in hot conditions.
The front bearing plate is upside down,Mercedes never fixed,there is a x marked on plate
to denote up when installed or front bearing will be starved of oil.