ΔE 7.1, close: similar, with a visible difference side by side. Pale Grey Blue is a little darker, more saturated than Royal Light Gray.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Pale Grey Blue is a little darker, more saturated than Royal Light Gray.
The same difference applies the other way round: Royal Light Gray 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 Royal Light Gray on the colour wheel See Pale Grey Blue on the colour wheel
All matches: Royal Light Gray equivalents · Pale Grey Blue equivalents