I can only imagine it’s chrome Dave, the caliper would have to be tank dipped before assembly and I just don’t see any practical way they could/would mask out that portion. I expect the decal is just thin aluminum held on by a strong adhesive. Getting it off without marking the chrome underneath would be the issue, you could make it look a right mess. What about carefully painting over the decal in silver or chrome like paint? See if you like it.