ΔE 6.9, close: similar, with a visible difference side by side. Fulgurite Copper is more saturated than True Copper.
Can I use Fulgurite Copper instead of True Copper?
Usually, if you are not matching paint already on the model. Close match (ΔE 7). Fulgurite Copper is more saturated than True Copper.
Can I use True Copper instead of Fulgurite Copper?
The same difference applies the other way round: True Copper is more muted.
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.