The exact date of manufacture is not in the VIN. There are lots of VIN decoders on the Internet. Here is one:
http://www.decodethis.com/Decoder/YourOwnV...76/Default.aspx which gives you this:
VIN JTJBT20X460111262 VALID Passengers 5 Date 1/11/2009
Year 2006 Doors 4 Invoice $40,571.00
Make Lexus Manual/Auto Trans. No / Std MSRP $46,635.00
Model GX 470 Forced Induction No Delivery $715.00
Trim FrontWD No Engine Type 8 Cylinder Engine
Style 4-Door SUV 4WD RearWD No Engine Size 4.7L/285 CID
Market 4WD Sport Utility Vehicles AllWD No Horsepower
Towing FourWD Std Torque
Fleet Only No Stepside No Fuel Type Gasoline Fuel
The month and year of manufacture should be on a sticker on the drivers door jam.
What kind of "official certificate" you are looking for? The VIN should be enough for an insurance company claim and they can figure out the rest.