F6 Green paint

Can anyone tell me if F6 green was a one year color only for 1969? A friend has a 69 Dart 340 GT Swinger in F6 green that he is restoring, and was told it was a 69 only color,(I kind of doubt it) & GM had the same color. Is any of this true? It is a rare color for this car. I don't think I've ever seen a Dart in F6. I've seen the car & has a lot of the original paint still on it, & fender tag is on it also to match the paint & VIN. I need your help on this. Thanks all.