ΔE 6.9, close: similar, with a visible difference side by side. Grey RLM02 is a little darker, warmer than Gray FS36231.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Grey RLM02 is a little darker, warmer than Gray FS36231.
The same difference applies the other way round: Gray FS36231 is a little lighter, 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 FS36231 on the colour wheel See Grey RLM02 on the colour wheel
All matches: Gray FS36231 equivalents · Grey RLM02 equivalents