ΔE 15.5, loose: different enough that you should pick on purpose. Undead Flesh is noticeably lighter, more muted, warmer than Light DAK Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 15). Undead Flesh is noticeably lighter, more muted, warmer than Light DAK Green.
The same difference applies the other way round: Light DAK Green 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 Light DAK Green on the colour wheel See Undead Flesh on the colour wheel
All matches: Light DAK Green equivalents · Undead Flesh equivalents