ΔE 6.4, close: similar, with a visible difference side by side. Khaki is more saturated, warmer than IDF Gray 1 (-1981 Sinai).
Usually, if you are not matching paint already on the model. Close match (ΔE 6). Khaki is more saturated, warmer than IDF Gray 1 (-1981 Sinai).
The same difference applies the other way round: IDF Gray 1 (-1981 Sinai) is more muted, 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 IDF Gray 1 (-1981 Sinai) on the colour wheel See Khaki on the colour wheel
All matches: IDF Gray 1 (-1981 Sinai) equivalents · Khaki equivalents