I have to admit I cheated and painted the calipers when they were new. The color new was a clear zinc color (very slight blue). I used a brush on super durable sliver caliper paint and then lightly sprayed a high temp gold color. The gold over silver gave it a yellow zinc look and the light coat dulled the finish to look plated.
Close enough for me and didn’t have to take them apart. I agree that the plated finish alone has a limited life span and it gets coated in brake dust. So what ever you use, it won’t stay pristine for long.
