ΔE 10.6, fair: the same colour family, but not a straight swap. Flanker Light Gray is a little darker than Longbeard Grey.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Flanker Light Gray is a little darker than Longbeard Grey.
The same difference applies the other way round: Longbeard Grey is a little lighter.
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 Longbeard Grey on the colour wheel See Flanker Light Gray on the colour wheel
All matches: Longbeard Grey equivalents · Flanker Light Gray equivalents