Speaking from the early days, there was a reason why professional cameras were black and consumer cameras were silver. The pro cameras were brass bodies. This didn't loook good, so they were painted. Black was the obvious choice. The consumer cameras were left silver because that's the color brushed aluminum was and it looked good. The original pro brass cameras were heavier duty and could take much more of a beating than the thinner and softer aluminum versions.

Later, when black caught on and everyone wanted a "pro" camera, they painted the aluminum bodies too and it all became meaningless...

Silver cameras will not 'brass' as there no brass underneath the silver color.... Excluding the few that were plated brass...