ΔE 7.2, close: similar, with a visible difference side by side. Gravestone Blue is a little darker, more saturated than Cadre Grey.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Gravestone Blue is a little darker, more saturated than Cadre Grey.
The same difference applies the other way round: Cadre 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 Cadre Grey on the colour wheel See Gravestone Blue on the colour wheel
All matches: Cadre Grey equivalents · Gravestone Blue equivalents