ΔE 13.0, fair: the same colour family, but not a straight swap. Grey Knights Steel is a little darker, more muted than Oily Steel.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Grey Knights Steel is a little darker, more muted than Oily Steel.
The same difference applies the other way round: Oily Steel is a little lighter, more saturated.
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 Oily Steel on the colour wheel See Grey Knights Steel on the colour wheel
All matches: Oily Steel equivalents · Grey Knights Steel equivalents