Dark Drab vs Light Green RLM82

How close are they?

ΔE 6.7, close: similar, with a visible difference side by side. Light Green RLM82 is a little lighter, warmer than Dark Drab.

Can I use Light Green RLM82 instead of Dark Drab?

Usually, if you are not matching paint already on the model. Close match (ΔE 7). Light Green RLM82 is a little lighter, warmer than Dark Drab.

Can I use Dark Drab instead of Light Green RLM82?

The same difference applies the other way round: Dark Drab 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.