ΔE 12.5, fair: the same colour family, but not a straight swap. Arcane Gold is noticeably darker than Heirloom Gold.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Arcane Gold is noticeably darker than Heirloom Gold.
The same difference applies the other way round: Heirloom 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 Heirloom Gold on the colour wheel See Arcane Gold on the colour wheel
All matches: Heirloom Gold equivalents · Arcane Gold equivalents