ΔE 7.6, close: similar, with a visible difference side by side. Desert Brown is a little darker, more saturated than Light Brown.
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Desert Brown is a little darker, more saturated than Light Brown.
The same difference applies the other way round: Light Brown is a little lighter, 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 Light Brown on the colour wheel See Desert Brown on the colour wheel
All matches: Light Brown equivalents · Desert Brown equivalents