ΔE 14.0, fair: the same colour family, but not a straight swap. Gold Brown is noticeably darker, more muted than Iridescent Bright Gold (Fine). They are different kinds of paint: Golden Iridescent Bright Gold (Fine) is a pearl paint and Vallejo Gold Brown is a metallic, so they won’t behave the same on the model even where the colour is close.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 14). Gold Brown is noticeably darker, more muted than Iridescent Bright Gold (Fine). They are different kinds of paint.
The same difference applies the other way round: Iridescent Bright Gold (Fine) is noticeably lighter, more saturated.
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 Bright Gold (Fine) on the colour wheel See Gold Brown on the colour wheel
All matches: Iridescent Bright Gold (Fine) equivalents · Gold Brown equivalents