ΔE 19.1, loose: different enough that you should pick on purpose. Chromium Oxide Green Dark is noticeably lighter, more saturated, warmer than Lupercal Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Chromium Oxide Green Dark is noticeably lighter, more saturated, warmer than Lupercal Green.
The same difference applies the other way round: Lupercal Green is noticeably darker, 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 Lupercal Green on the colour wheel See Chromium Oxide Green Dark on the colour wheel
All matches: Lupercal Green equivalents · Chromium Oxide Green Dark equivalents