Apparently they produced the color in 1967. Here's some info.
Dusk Rose was a Standard Ford Mustang color, but only used in small amounts for a very short time (about 6 months). Mustangs that bear this color can be recognized by the 'S' color code on the Vehicle Data Plate, attached to the door. If you have a '67 Mustang in a slightly different color, but with the 'S' code, it probably began its life as a pink one. The color got it's name 'Dusk Rose' from a '57 Ford Thunderbird color code with the same name. It is not certain (yet) that these two colors are in fact the same. Nobody ever checked, Ford used a number of different pinks throughout the fifties and sixties and the legendary 'Playboy Pink' or 'Playmate Pink', for example, is slightly darker than 'Dusk Rose' and appears to be based on a 50's Lincoln color.