ΔE 12.4, fair: the same colour family, but not a straight swap. Olive Drab is noticeably darker than Thicket Grove.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Olive Drab is noticeably darker than Thicket Grove.
The same difference applies the other way round: Thicket Grove is noticeably lighter.
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 Thicket Grove on the colour wheel See Olive Drab on the colour wheel
All matches: Thicket Grove equivalents · Olive Drab equivalents