ΔE 11.3, fair: the same colour family, but not a straight swap. Aged Metal is a little darker, cooler than Steampunk Copper.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Aged Metal is a little darker, cooler than Steampunk Copper.
The same difference applies the other way round: Steampunk Copper is a little lighter, 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 Steampunk Copper on the colour wheel See Aged Metal on the colour wheel
All matches: Steampunk Copper equivalents · Aged Metal equivalents