ΔE 7.6, close: similar, with a visible difference side by side. Steel Helmet Green is more muted than Nº1 Light Green (FS34151).
Usually, if you are not matching paint already on the model. Close match (ΔE 8). Steel Helmet Green is more muted than Nº1 Light Green (FS34151).
The same difference applies the other way round: Nº1 Light Green (FS34151) is more saturated.
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 Nº1 Light Green (FS34151) on the colour wheel See Steel Helmet Green on the colour wheel
All matches: Nº1 Light Green (FS34151) equivalents · Steel Helmet Green equivalents