The 12/6 stamp is the date the dealer delivered it to the first owner. Thats what the DD stands for on the VIN tag Delivery Date (or Dealer Deleivery) and it was intended t be used as the start of the warrantee period. Very few dealers actually stamped the date on the VIN tag. Car was probably a dealer demo car for the first 3 months of its life, then sold in December.