Skeleton Bone vs Deck Grey

How close are they?

ΔE 6.3, close: similar, with a visible difference side by side. Deck Grey is a little lighter, warmer than Skeleton Bone.

Can I use Deck Grey instead of Skeleton Bone?

Usually, if you are not matching paint already on the model. Close match (ΔE 6). Deck Grey is a little lighter, warmer than Skeleton Bone.

Can I use Skeleton Bone instead of Deck Grey?

The same difference applies the other way round: Skeleton Bone is a little darker, 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.