ΔE 18.3, loose: different enough that you should pick on purpose. Plague Brown is noticeably darker, more saturated, warmer than Radome.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 18). Plague Brown is noticeably darker, more saturated, warmer than Radome.
The same difference applies the other way round: Radome is noticeably lighter, 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 Radome on the colour wheel See Plague Brown on the colour wheel
All matches: Radome equivalents · Plague Brown equivalents