ΔE 13.1, fair: the same colour family, but not a straight swap. Ghoul Skin is much more muted, warmer than Olive Drab.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Ghoul Skin is much more muted, warmer than Olive Drab.
The same difference applies the other way round: Olive Drab is much 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 Olive Drab on the colour wheel See Ghoul Skin on the colour wheel
All matches: Olive Drab equivalents · Ghoul Skin equivalents