ΔE 19.4, loose: different enough that you should pick on purpose. Khaki Drill is a little lighter, more muted than Mars Yellow. They are different kinds of paint: Golden Mars Yellow is an opaque base/layer paint and Vallejo Khaki Drill is a one-coat contrast-style paint, so they won’t behave the same on the model even where the colour is close.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 19). Khaki Drill is a little lighter, more muted than Mars Yellow. They are different kinds of paint.
The same difference applies the other way round: Mars Yellow is a little darker, more saturated.
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 Mars Yellow on the colour wheel See Khaki Drill on the colour wheel
All matches: Mars Yellow equivalents · Khaki Drill equivalents