ΔE 18.7, loose: different enough that you should pick on purpose. Flak Gun Yellow is noticeably lighter, cooler than Camo Sand.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Flak Gun Yellow is noticeably lighter, cooler than Camo Sand.
The same difference applies the other way round: Camo Sand is noticeably darker, 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 Camo Sand on the colour wheel See Flak Gun Yellow on the colour wheel
All matches: Camo Sand equivalents · Flak Gun Yellow equivalents