ΔE 12.9, fair: the same colour family, but not a straight swap. Shadow Flesh is noticeably darker, warmer than Weathered Skin.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Shadow Flesh is noticeably darker, warmer than Weathered Skin.
The same difference applies the other way round: Weathered Skin is noticeably lighter, 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 Weathered Skin on the colour wheel See Shadow Flesh on the colour wheel
All matches: Weathered Skin equivalents · Shadow Flesh equivalents