ΔE 17.2, loose: different enough that you should pick on purpose. Saddle Brown is noticeably lighter, more muted, warmer than Black Skintone.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Saddle Brown is noticeably lighter, more muted, warmer than Black Skintone.
The same difference applies the other way round: Black Skintone is noticeably darker, more saturated, 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.
See Black Skintone on the colour wheel See Saddle Brown on the colour wheel
All matches: Black Skintone equivalents · Saddle Brown equivalents