Another way which is IMO much easier to find resources. Download
openBRF tool. It is extremely useful.
You can find in a mod's Resource folder for Napoleonic Wars: mm_colours.brf
Open that and browse the mesh items for the colours you are looking for, click on the Material name in the middle panel of the openBRF program and then click on DiffuseA in the MAT tab to jump to the texture.