ΔE 18.8, loose: different enough that you should pick on purpose. Retributor Armour is noticeably darker, warmer than Brass.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Retributor Armour is noticeably darker, warmer than Brass.
The same difference applies the other way round: Brass is noticeably lighter, cooler.
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 Brass on the colour wheel See Retributor Armour on the colour wheel
All matches: Brass equivalents · Retributor Armour equivalents