ΔE 6.5, close: similar, with a visible difference side by side. Navy Blue is a little lighter, cooler than Russian Blue Lights.
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Navy Blue is a little lighter, cooler than Russian Blue Lights.
The same difference applies the other way round: Russian Blue Lights 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 Russian Blue Lights on the colour wheel See Navy Blue on the colour wheel
All matches: Russian Blue Lights equivalents · Navy Blue equivalents