In actuality few, if any, current light bars have any chrome plated parts. To me it's just more convenient spraying the entire thing aluminum, then adding some "shint stuff" for the rotators. With the proliferation of LED bars it is really easier. The majority look clear until turned on so just paint the inside of the clear area silver.
In all honesty though from 3 feet you won't notice the rotators at all until they are turned on. So since looking at a model from one foot away is like 24 actual feet, it just depends on how much you want to add.
I'm liking this kit and cannot wait to get started.
G