In Corona Physical Mtl models, the color of the cushions is set through CoronaMulti Texmap, and it can be changed as desired.

For Corona render, it is recommended to use a version no lower than 1.5, as the glossiness of the materials is set with PBR in mind. Those working in V-Ray versions lower than 3.1 should be careful; the materials in the BRDF section are set to Microfacet GTR (GGX). If your version is older than 3.1, the BRDF field will be empty. Choose Blinn, Phong, or Ward – whichever is preferable for you.