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