DSO has a dual meaning on a door data plate or build sheet. When the code is two digits long, it indicates the District Sales Office for which the order was intended. When a dealership ordered a car, they didn’t contact Ford directly. They went through their District Sales Office. For instance, a dealer in Bradford, PA with a dealer number of 37J551 on January 16, 1966 would have had a home office of Buffalo, New York (District #37).
If a car was to be built with non-standard production features, a six-digit code was stamped on the door tag. The first two digits still indicated the District Sales Office responsible for the order. The last four digits were a Special Order Number to keep track of the order and were indicated in the DSO/FSO/PTO line of the build sheet.
According to Kevin Marti, there were four types of special orders:
- · DSO - Domestic Special Order, which included Shelbys and Boss 429’s
- · FSO - Foreign Special Orders
- · PTO - Paint & Tire Orders, which included special paint and special tire usage
- · SPO - Special Production Orders
For instance, if a dealer special-ordered five Mustangs for a promotion in a non-stock paint color, such as a Thunderbird Sapphire Blue, all five Mustangs would have the same six digit DSO code, ie. 24-0327, with 24 being the ordering sales office (Jacksonville, FL), and 0327 being the Special Order Number (sequential).
Below is a punchcard obtained from Charles Turner, with the areas in yellow indicating the location of the Special Order Number as it was first assigned by Ford. If the car had no unusual features, these areas were normally blank, as in the case of Charles’ punchcard. Below that is an export build sheet with a four-digit FSO.