ΔE 10.2, fair: the same colour family, but not a straight swap. Light Gray is a little lighter than Dark Elf Highlight.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 10). Light Gray is a little lighter than Dark Elf Highlight.
The same difference applies the other way round: Dark Elf Highlight is a little darker.
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 Dark Elf Highlight on the colour wheel See Light Gray on the colour wheel
All matches: Dark Elf Highlight equivalents · Light Gray equivalents