Cad plating may no longer be an option in most countries due to environmental impact of cadmium.....so zinc plating tends to be the most environmentally acceptable option with either a yellow chromated or yellow iridite dichromated finish.
You can still find Cad plating. But, most suppliers don't want to do auto restoration and/or won't take the time and care with your parts - catalog them and return without loss, etc.
This outfit will. Not cheap though: Plating by Queen City Plating Inc.