............For a 66 I assume it should read WM 0 66 2. (Just want to make sure)
For a Mustang the top tank is a
1- completely different shape top tank,
2- stamping runs horizontal to the long sides of the top tank,
3- the fonts are larger,
4- a "-" dash between the "W" and the "MO"
5- the date format is month then year not the other way around as done in 67.