Took a second look and found this. The color is called A22, which would be army. The formula is for old Pactra colors. I've tried to match them to Model Master as best as my poor eyesight can. You can always plead fading or a bad batch from the factory.
1 part flat black
2 parts interior green FS 34151
4 parts true blue FS 15102
The blue is the one I had the most trouble with. The Pactra color is M3 Navy Blue.