ΔE 15.3, loose: different enough that you should pick on purpose. Steel Legion Drab is a little lighter, warmer than Nº9 Olive Drab (FS33070).
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Steel Legion Drab is a little lighter, warmer than Nº9 Olive Drab (FS33070).
The same difference applies the other way round: Nº9 Olive Drab (FS33070) 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 Nº9 Olive Drab (FS33070) on the colour wheel See Steel Legion Drab on the colour wheel
All matches: Nº9 Olive Drab (FS33070) equivalents · Steel Legion Drab equivalents