ΔE 21.8, loose: different enough that you should pick on purpose. Moon Yellow is noticeably lighter, much more saturated, cooler than Moldy Ochre.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 22). Moon Yellow is noticeably lighter, much more saturated, cooler than Moldy Ochre.
The same difference applies the other way round: Moldy Ochre is noticeably darker, much more muted, 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 Moldy Ochre on the colour wheel See Moon Yellow on the colour wheel
All matches: Moldy Ochre equivalents · Moon Yellow equivalents