ΔE 14.6, fair: the same colour family, but not a straight swap. Zombie Flesh is a little darker, more saturated than Gravelord Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Zombie Flesh is a little darker, more saturated than Gravelord Grey.
The same difference applies the other way round: Gravelord 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 Gravelord Grey on the colour wheel See Zombie Flesh on the colour wheel
All matches: Gravelord Grey equivalents · Zombie Flesh equivalents