ΔE 9.2, close: similar, with a visible difference side by side. USAAF Light Gray is a little lighter, more muted, warmer than Pastel Green.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). USAAF Light Gray is a little lighter, more muted, warmer than Pastel Green.
The same difference applies the other way round: Pastel Green is a little darker, more saturated, cooler.
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 Pastel Green on the colour wheel See USAAF Light Gray on the colour wheel
All matches: Pastel Green equivalents · USAAF Light Gray equivalents