ΔE 21.7, loose: different enough that you should pick on purpose. IDF/IAF Green is noticeably darker, much more saturated than Moonstone Grey.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). IDF/IAF Green is noticeably darker, much more saturated than Moonstone Grey.
The same difference applies the other way round: Moonstone Grey is noticeably lighter, much more muted.
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 Moonstone Grey on the colour wheel See IDF/IAF Green on the colour wheel
All matches: Moonstone Grey equivalents · IDF/IAF Green equivalents