Mopar paint codes that keep the same code, Y9, for example will be the same across the model lines and often they will be used for several years. If you have the build sheet for the car, the first digit of the paint code on the sheet will give you the first year that color was used. FP6 for example uses the F as the year the color was first used = 1970. (Paint codes use the same letter designation as engine blocks etc) The formula for the paint will be the same in later years as paint code changes will be reflected with a new first year of use. Any time a paint mixture changes, there will be a new first digit. This sometimes gets confusing since a new color will have the specifics for its formula for the first year of use that will not appear in the subsequent data for later years of use. The important thing to remember is that the code, one established is the same formula no matter when or where it was used on the Mopar line. I can also tell you that the paints with lots of metal particulate in them can be very difficult to match due to the way the paint ages and differences in how the finish is applied.
Dave