Also grill itself (I think implied but for clarity), the Mach 1 cast aluminum rocker molding. Also the wheel covers that most of the Mach 1s came with have argent paint on them.
The rear honeycomb panel is a matter of debate. To my understanding it was not painted (that seems fairly well agreed) however some are saying true originals were molded in argent or dark grey colored plastic, where as at least some later produced NOS panels were done in black plastic. I have never held in my hand an original panel so I cant contribute to the discussion. For my own restoration I will need an answer myself.