ΔE 19.3, loose: different enough that you should pick on purpose. Rusty Metal is noticeably darker, more muted than Cold Steel.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Rusty Metal is noticeably darker, more muted than Cold Steel.
The same difference applies the other way round: Cold Steel is noticeably lighter, 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 Cold Steel on the colour wheel See Rusty Metal on the colour wheel
All matches: Cold Steel equivalents · Rusty Metal equivalents