A quick clarification for you-
383 refers to the green/brown/black camo scheme itself.
The FS codes for the actual colours are Green 34094, Brown 30051, and Black 37030 (though any good flat black will do).
Likewise, 686 refers to the tan camo, the actual colour is Tan 33446.
If you buy your paint from one of the MV hobby dealers, they will know what you are talking about right away. If you get paint from a 'regular' paint dealer, you will need to give them the FS code.
I also have had good luck using the Gillespie paint from Rapco.
Cheers