ΔE 6.6, close: similar, with a visible difference side by side. Desert Olive Green is a little lighter, cooler than IJN J3 SP (Amber Grey).
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Desert Olive Green is a little lighter, cooler than IJN J3 SP (Amber Grey).
The same difference applies the other way round: IJN J3 SP (Amber Grey) is a little darker, warmer.
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 IJN J3 SP (Amber Grey) on the colour wheel See Desert Olive Green on the colour wheel
All matches: IJN J3 SP (Amber Grey) equivalents · Desert Olive Green equivalents