Mercedes-Benz 2007 GL 320 CDI Operator's Manual page 552

Second-row seat
4 VIN
Fold the carpet forwards.
The VIN 4 is now visible.
i
When ordering parts, please specify vehicle
identification and engine numbers.
5 Emission control information label,
includes both federal and California
certification exhaust emission
standards
6 Engine number (engraved on engine)
7 Vacuum line routing diagram label
8 VIN, visible (lower edge of windshield)
Technical data
Identification labels
551