Yes, leave it there. Saw the same thing when I swapped out the units in my W124. The OEM unit still had it in place, so I left it alone.
Perhaps someone knows exactly why it's there? Or is this along the same lines as mattress tags?
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car