ΔE 25.5, loose: different enough that you should pick on purpose. Aged Metal is noticeably darker, much more saturated than Iridescent Stainless Steel (Coarse). They are different kinds of paint: Golden Iridescent Stainless Steel (Coarse) is a pearl paint and Vallejo Aged Metal is a metallic, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 26). Aged Metal is noticeably darker, much more saturated than Iridescent Stainless Steel (Coarse). They are different kinds of paint.
The same difference applies the other way round: Iridescent Stainless Steel (Coarse) is noticeably lighter, much more muted.
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 Iridescent Stainless Steel (Coarse) on the colour wheel See Aged Metal on the colour wheel
All matches: Iridescent Stainless Steel (Coarse) equivalents · Aged Metal equivalents