ΔE 17.6, loose: different enough that you should pick on purpose. Gryph-Charger Grey is noticeably lighter, more saturated than Gravelord Grey.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Gryph-Charger Grey is noticeably lighter, more saturated than Gravelord Grey.
The same difference applies the other way round: Gravelord Grey is noticeably darker, 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 Gravelord Grey on the colour wheel See Gryph-Charger Grey on the colour wheel
All matches: Gravelord Grey equivalents · Gryph-Charger Grey equivalents