ΔE 9.9, close: similar, with a visible difference side by side. Plague Brown is a little lighter, more saturated than Sandgelb RLM 79.
Usually, if you are not matching paint already on the model. Close match (ΔE 10). Plague Brown is a little lighter, more saturated than Sandgelb RLM 79.
The same difference applies the other way round: Sandgelb RLM 79 is a little darker, 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 Sandgelb RLM 79 on the colour wheel See Plague Brown on the colour wheel
All matches: Sandgelb RLM 79 equivalents · Plague Brown equivalents