For sure Secluff is our resident Ford dealer guy.
Ford only made 71 - 73 Mustangs in four places. The start of 71 has N.J. as an assembly plant. That was shut down and all of the 72 & 73 came out of Michigan. Of course the Mexican models were made in Mexico and the 73 Sprint models have really cool two tone paint job.
There was no assembly plant in Canada but lots of parts were made in Canada.
The only other place they assembled Mustangs was by the Dutch. Here is a link to some info.
http://www.mustangdrivers.be/dutchmustangs.htm
As some have mentioned you should get you a copy of Mustang by the Numbers that Marti put together. It is not 100% for some reason he leaves some options off his lists.
You will also see in the book that Ford built lot of odd ball mustangs. You could order any color you wanted that Ford had as a stock color. They called it Special Paint & Trim option. Marti has the number they made he did not get the specifics of what each one involved. If it was for a non Mustang paint there is no paint code on the door sticker and will have a six digit DSO code. There are several here on the forum I have a 73 vert that is non factory color.
With that being said you could have ordered a Q code spring special with 4 speed and it could have been any color Ford had offered. With the rubber front bumper in 71 & 72 Ford would switch to a chrome even on a Mach 1. In 73 there were no chrome so the put Argent front bumpers on.
Ford offered the ability to get any color for every year of Mustang. Here is a couple pics of one of the very early 1964 1/2. Had a 1940 Lincoln color and had real leather seats. Has the six digit DSO code and there is actually a registry for them.
There are lots of odd Mustangs out there and many just blow it off as the owner change it but Ford would do lots of trim and color changes. They could not say put you a 351 W in 71-73 because it was never certified for government requirements. The Door sticker on our cars is called the "Certification Label" by Ford the dash tag is the "Official Vehicle Identificaiton Number.
Was looking a 67 model coupe the other day on Facebook everyone was telling him it had a color change that no Mustangs that model got Calypso Coral but his car was. I got in touch with him and it had the six digit DSO and no paint code. It was a one of the Special Paint cars so it is really rare.
Here is a copy of my Marti for the 73 vert I have with all the info. I also was lucky to have a build sheet and it states to install the Argent front bumper. Couple pics of the 64 1/2 with non factory options installed by Ford.
Ford did some odd Mustangs some got out to public some did not. The one automatic Boss 429 did not get to the public and it was also a mid engine model. The two Boss 429 Cougars did get to public and have been found.
View attachment 3F03H228536_dlxrpt.pdf