ΔE 13.7, fair: the same colour family, but not a straight swap. Death Korps Drab is a little darker, more saturated, warmer than Field Grey FS-34159.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Death Korps Drab is a little darker, more saturated, warmer than Field Grey FS-34159.
The same difference applies the other way round: Field Grey FS-34159 is a little lighter, more muted, 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 Field Grey FS-34159 on the colour wheel See Death Korps Drab on the colour wheel
All matches: Field Grey FS-34159 equivalents · Death Korps Drab equivalents