ΔE 12.9, fair: the same colour family, but not a straight swap. Olive Drab is much more saturated than Eshin Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Olive Drab is much more saturated than Eshin Grey.
The same difference applies the other way round: Eshin Grey is much more muted.
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 Eshin Grey on the colour wheel See Olive Drab on the colour wheel
All matches: Eshin Grey equivalents · Olive Drab equivalents