ΔE 35.6, loose: different enough that you should pick on purpose. Sunny Yellow is noticeably lighter, warmer than Gladeshard.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 36). Sunny Yellow is noticeably lighter, warmer than Gladeshard.
The same difference applies the other way round: Gladeshard is noticeably darker, 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 Gladeshard on the colour wheel See Sunny Yellow on the colour wheel
All matches: Gladeshard equivalents · Sunny Yellow equivalents