ΔE 12.5, fair: the same colour family, but not a straight swap. German Orange is a little lighter, more saturated, cooler than Rust in Peace.
Only where an exact match doesn’t matter, such as a new unit or a highlight. Fair match (ΔE 12). German Orange is a little lighter, more saturated, cooler than Rust in Peace.
The same difference applies the other way round: Rust in Peace is a little darker, 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 Rust in Peace on the colour wheel See German Orange on the colour wheel
All matches: Rust in Peace equivalents · German Orange equivalents