ΔE 12.4, fair: the same colour family, but not a straight swap. Light Umber is a little darker, more saturated than Steel Legion Drab.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). Light Umber is a little darker, more saturated than Steel Legion Drab.
The same difference applies the other way round: Steel Legion Drab is a little lighter, 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 Steel Legion Drab on the colour wheel See Light Umber on the colour wheel
All matches: Steel Legion Drab equivalents · Light Umber equivalents