ΔE 12.4, fair: the same colour family, but not a straight swap. Death World Forest is a little darker, more saturated, cooler than Rock Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Death World Forest is a little darker, more saturated, cooler than Rock Grey.
The same difference applies the other way round: Rock Grey is a little lighter, more muted, warmer.
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 Rock Grey on the colour wheel See Death World Forest on the colour wheel
All matches: Rock Grey equivalents · Death World Forest equivalents