ΔE 16.6, loose: different enough that you should pick on purpose. Van Dyke Brown Hue is noticeably darker, more muted, cooler than Gorthor Brown.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 17). Van Dyke Brown Hue is noticeably darker, more muted, cooler than Gorthor Brown.
The same difference applies the other way round: Gorthor Brown is noticeably lighter, more saturated, warmer.
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 Gorthor Brown on the colour wheel See Van Dyke Brown Hue on the colour wheel
All matches: Gorthor Brown equivalents · Van Dyke Brown Hue equivalents