ΔE 10.2, fair: the same colour family, but not a straight swap. Mustard Brown is a little lighter, more saturated than Sylvaneth Bark.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Mustard Brown is a little lighter, more saturated than Sylvaneth Bark.
The same difference applies the other way round: Sylvaneth Bark 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 Sylvaneth Bark on the colour wheel See Mustard Brown on the colour wheel
All matches: Sylvaneth Bark equivalents · Mustard Brown equivalents