1. Align the installation holes of the front license plate with the dimples on the front bumper.
2. Install two (2) self-tapping screws through the license plate and into the front bumper at the dimples.
NOTE: Do NOT drill holes into the bumper.
Use self-tapping screws of a non-corroding type with the following dimensions:
Nominal Length: 20.0 mm (0.79 in.)
Diameter: 6.0 mm (0.24 in.)
This is from TSB
PD113-06 FRONT LICENSE PLATE INSTALLATION DURING PDS for 2007 model year Sienna vehicles