ΔE 26.2, loose: different enough that you should pick on purpose. Salmon Rose is noticeably darker, warmer than Light Magenta.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 26). Salmon Rose is noticeably darker, warmer than Light Magenta.
The same difference applies the other way round: Light Magenta is noticeably lighter, 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 Light Magenta on the colour wheel See Salmon Rose on the colour wheel
All matches: Light Magenta equivalents · Salmon Rose equivalents