ΔE 16.6, loose: different enough that you should pick on purpose. Darkoath Flesh is noticeably darker, more saturated than Bony Matter.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Darkoath Flesh is noticeably darker, more saturated than Bony Matter.
The same difference applies the other way round: Bony Matter is noticeably 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 Bony Matter on the colour wheel See Darkoath Flesh on the colour wheel
All matches: Bony Matter equivalents · Darkoath Flesh equivalents