ΔE 14.7, fair: the same colour family, but not a straight swap. Russian AF Grey N.3 is noticeably lighter than N4 Neutral Gray.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Russian AF Grey N.3 is noticeably lighter than N4 Neutral Gray.
The same difference applies the other way round: N4 Neutral Gray is noticeably darker.
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 N4 Neutral Gray on the colour wheel See Russian AF Grey N.3 on the colour wheel
All matches: N4 Neutral Gray equivalents · Russian AF Grey N.3 equivalents