ΔE 6.8, close: similar, with a visible difference side by side. Steel Legion Drab is a little lighter, warmer than Khaki green No.3.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Steel Legion Drab is a little lighter, warmer than Khaki green No.3.
The same difference applies the other way round: Khaki green No.3 is a little darker, 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 Khaki green No.3 on the colour wheel See Steel Legion Drab on the colour wheel
All matches: Khaki green No.3 equivalents · Steel Legion Drab equivalents