Oiled Leather vs Red Leather

How close are they?

ΔE 7.7, close: similar, with a visible difference side by side. Red Leather is a little lighter, cooler than Oiled Leather.

Can I use Red Leather instead of Oiled Leather?

Usually, if you are not matching paint already on the model. Close match (ΔE 8). Red Leather is a little lighter, cooler than Oiled Leather.

Can I use Oiled Leather instead of Red Leather?

The same difference applies the other way round: Oiled Leather is a little darker, 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.