ΔE 14.1, fair: the same colour family, but not a straight swap. Saddle Brown is a little darker, more saturated than Warm Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Saddle Brown is a little darker, more saturated than Warm Grey.
The same difference applies the other way round: Warm Grey 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 Warm Grey on the colour wheel See Saddle Brown on the colour wheel
All matches: Warm Grey equivalents · Saddle Brown equivalents