From the website:
http://fendermustangstory.com/ (links are found at the website...)
The biggest change to the Mustang occurred in 1969. The forearm contour and the back contour are added to the body. This marks the end of the slab bodied Mustangs. The "Made-In-Japan Fender '69 Mustangs" are reissue of this era of Mustangs. Also, this is the year the Competition Mustangs were introduced. Basically, the Competition Mustangs are Mustangs with different paint scheme.
They came in Competition Red (w/cream stripes), Competition Burgandy (Blue)(w/light blue stripes), and Competition Orange (w/dark orange stripes) colors with contrasting racing strips right around the forearm contour on the front side of the body. The stripes were "thin-thick-thin" stripes with the base body color showing between the stripes. The stripes were only applied on the front of the body and not on the back. The Competition models apparently came standard with matching headstocks. However, there are a significant number of these Competition Mustangs with non-matching headstocks, so it may have been sold both ways. My guess would be that the earlier ('69 through mid-'71) Competitions all had matching headstocks and the later (mid-'71 through '72) ones had non-matching headstocks. The Competition "Burgandy" color has been puzzling to me for a while as "burgandy" to mean means a reddish color with a blue hue or something close to the color purple. Fender had a custom color called "Burgandy Mist Metallic" which would be described as "light purple." But in my search on the web, I found a reference to the color "burgandy" being associated to a dark blue color in one of the car advertisement of the 60s. I guess that's where the burgandy-blue color reference Fender used came from. I always thought somebody at Fender screwed up and accidentally called the dark blue guitar "burgandy"...
And below that...
Around 1970, the regular Mustangs were discontinued and replaced by the Competition Mustangs. None of the feature on Mustangs really change until about 1973 and since a '67 Mustang isn't really worth more than a '72 Mustang, I don't think anybody really took great interest during this era unlike the more expensive Stratocasters and Telecasters. Besides, Fender stopped dating the neck in this time frame and started using codes that require deciphering, making it doubly difficult to tell the manufacture date (yes, you can still look at the pot dates). Greg Gagliano has deciphered the neck coding of this era, check his article out in the link just below.
I know as a fact that there are Red, White, and Blue Mustangs with body contours so my guess would be that the regular Mustangs continued into 1969 and was replaced by the Competition Mustangs sometime during 1969. The Competition Mustangs were made in lefty versions also, although they were probably a special order item.
Here's a 1970 Fender Color Chart. It shows the following colors for the Mustang:
510 Competition Orange
511 Competition Burgandy
512 Competition Red
This chart also shows the plain "Red" (color code 515) and plain "Blue" (color code 517) used on the Musicmasters and Duo-Sonic. These colors were used on the pre-'69 Mustangs and were not called "Dakota Red" or "Daphne Blue." Competition Orange is not shown on the 1972 Color Chart so it looks like this color was dropped after one or two years.