ΔE 6.8, close: similar, with a visible difference side by side. Light Blue RLM76 is a little lighter, warmer than Gray FS36375.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Light Blue RLM76 is a little lighter, warmer than Gray FS36375.
The same difference applies the other way round: Gray FS36375 is a little darker, cooler.
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 Gray FS36375 on the colour wheel See Light Blue RLM76 on the colour wheel
All matches: Gray FS36375 equivalents · Light Blue RLM76 equivalents