ΔE 17.2, loose: different enough that you should pick on purpose. Imperial Gold is a little darker, much more saturated, warmer than Iridescent Gold (Fine). They are different kinds of paint: Golden Iridescent Gold (Fine) is a pearl paint and Vallejo Imperial Gold is a metallic, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Imperial Gold is a little darker, much more saturated, warmer than Iridescent Gold (Fine). They are different kinds of paint.
The same difference applies the other way round: Iridescent Gold (Fine) is a little lighter, much more muted, 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 Iridescent Gold (Fine) on the colour wheel See Imperial Gold on the colour wheel
All matches: Iridescent Gold (Fine) equivalents · Imperial Gold equivalents