ΔE 10.6, fair: the same colour family, but not a straight swap. USAF Light Gray is a little darker than Moon Mist Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). USAF Light Gray is a little darker than Moon Mist Grey.
The same difference applies the other way round: Moon Mist Grey is a little lighter.
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 Moon Mist Grey on the colour wheel See USAF Light Gray on the colour wheel
All matches: Moon Mist Grey equivalents · USAF Light Gray equivalents