ΔE 17.0, loose: different enough that you should pick on purpose. Dark Gunmetal is noticeably lighter, more muted than Green Pearl.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Dark Gunmetal is noticeably lighter, more muted than Green Pearl.
The same difference applies the other way round: Green Pearl is noticeably darker, 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 Green Pearl on the colour wheel See Dark Gunmetal on the colour wheel
All matches: Green Pearl equivalents · Dark Gunmetal equivalents