Old Bronze vs Aged Metal

How close are they?

ΔE 9.9, close: similar, with a visible difference side by side. Aged Metal is a little lighter, cooler than Old Bronze.

Can I use Aged Metal instead of Old Bronze?

Usually, if you are not matching paint already on the model. Close match (ΔE 10). Aged Metal is a little lighter, cooler than Old Bronze.

Can I use Old Bronze instead of Aged Metal?

The same difference applies the other way round: Old Bronze 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.