ΔE 14.6, fair: the same colour family, but not a straight swap. Rusty Metal is noticeably lighter than Spartan Bronze.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 15). Rusty Metal is noticeably lighter than Spartan Bronze.
The same difference applies the other way round: Spartan Bronze is noticeably darker.
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 Spartan Bronze on the colour wheel See Rusty Metal on the colour wheel
All matches: Spartan Bronze equivalents · Rusty Metal equivalents