ΔE 12.9, fair: the same colour family, but not a straight swap. True Brass is noticeably darker, cooler than Brass.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). True Brass is noticeably darker, cooler than Brass.
The same difference applies the other way round: Brass is noticeably 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 Brass on the colour wheel See True Brass on the colour wheel
All matches: Brass equivalents · True Brass equivalents