ΔE 8.9, close: similar, with a visible difference side by side. Olive Brown is a little darker, more muted than Mud Spatter.
Usually, if you are not matching paint already on the model. Close match (ΔE 9). Olive Brown is a little darker, more muted than Mud Spatter.
The same difference applies the other way round: Mud Spatter is a little lighter, more saturated.
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 Mud Spatter on the colour wheel See Olive Brown on the colour wheel
All matches: Mud Spatter equivalents · Olive Brown equivalents