Ford, Shelby and the FBI
Although Ford offered the Shelby GT 350 and GT 500 in 1970, the truth is they built those cars in 1969, selling the leftovers a year later. But to do that, Ford decided to change the VIN numbers to 1970 codes. However, it proved to be much more difficult than anybody expected.
In fact, the U.S. government sent their FBI agents to make the changes. The problem is that changing VIN numbers is a federal offense. So, a federal agency must perform this action in order to do it right. If you own a 1970 Shelby, the FBI probably approved it early in its life.