ΔE 12.9, fair: the same colour family, but not a straight swap. Inner Light is a little lighter, much more muted than Light Rust.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 13). Inner Light is a little lighter, much more muted than Light Rust.
The same difference applies the other way round: Light Rust is a little darker, much 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 Light Rust on the colour wheel See Inner Light on the colour wheel
All matches: Light Rust equivalents · Inner Light equivalents