ΔE 12.3, fair: the same colour family, but not a straight swap. Ghost Green is noticeably lighter, cooler than Gray FS16440.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Ghost Green is noticeably lighter, cooler than Gray FS16440.
The same difference applies the other way round: Gray FS16440 is noticeably darker, warmer.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Gray FS16440 on the colour wheel See Ghost Green on the colour wheel
All matches: Gray FS16440 equivalents · Ghost Green equivalents