ΔE 11.4, fair: the same colour family, but not a straight swap. Imperial Gold is noticeably darker than Old Gold.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 11). Imperial Gold is noticeably darker than Old Gold.
The same difference applies the other way round: Old Gold is noticeably lighter.
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 Old Gold on the colour wheel See Imperial Gold on the colour wheel
All matches: Old Gold equivalents · Imperial Gold equivalents