Apperances of 'copied' components?

Relatively new to Assemblies. One of the components is a copy of the other one. I would like to have different appearances (colour coding to denote left and right). When I change the appearance of a face of one of them, the other component is getting updated with the same appearance. How can I change that? Is there a workaround where I don't have to remove and insert a 'new' component?

Thanks in advance for your help!

SolidworksModeling And Assemblies