In most models the last 6 digits of the chassis number are not the same as the last 6 digits of the US VIN. A 123.123 is a 240D which should have a US VIN like WDBAB23A1C... where AB23 is the US VIN designation for a 123.123. My guess is the last 6 digits of the VIN in the windshield pillar or DMV papers is different from the last 6 digits of the chassis number on the radiator frame.

Sixto
95 S420
91 300SE
87 300SDL
83 300SD