Tires: Tire codes, digits, ww

Question
Hello,
I just watched the ABC special about dates on tires and how to decipher which year tires were made.  I checked my van and all my tires are from 2006.  I checked the tires on my husbands 2007 truck (which he purchased from a dealership) and the last for digits of the code is not there on any of the tires.  I know I'm looking in the right spot.  My husband thinks that may be the case for tires that are OEM?  We're not sure.
Thanks

Answer
Jennifer,

 Some makers DO NOT put the date codes on both sides of the tire most often when the tires are WW or white lettered.  OE tires ARE required to have the DOT molded into the tire also.  Fact is, ANY tires produced for sale in the U.S. MOST have DOT coding.