ΔE 18.3, loose: different enough that you should pick on purpose. Dark Flesh is noticeably lighter, more saturated than Leather Brown.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Dark Flesh is noticeably lighter, more saturated than Leather Brown.
The same difference applies the other way round: Leather Brown is noticeably darker, 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 Leather Brown on the colour wheel See Dark Flesh on the colour wheel
All matches: Leather Brown equivalents · Dark Flesh equivalents