ΔE 10.6, fair: the same colour family, but not a straight swap. Middle Stone is more saturated, warmer than RLM 02 Gray.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Middle Stone is more saturated, warmer than RLM 02 Gray.
The same difference applies the other way round: RLM 02 Gray is more muted, cooler.
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 RLM 02 Gray on the colour wheel See Middle Stone on the colour wheel
All matches: RLM 02 Gray equivalents · Middle Stone equivalents