ΔE 20.0, loose: different enough that you should pick on purpose. Gryph-Hound Orange is noticeably lighter, much more saturated than Hardened Leather.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 20). Gryph-Hound Orange is noticeably lighter, much more saturated than Hardened Leather.
The same difference applies the other way round: Hardened Leather is noticeably darker, much 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.
See Hardened Leather on the colour wheel See Gryph-Hound Orange on the colour wheel
All matches: Hardened Leather equivalents · Gryph-Hound Orange equivalents