What Tok said. The older models did not have the black coating. That's all it is--- a coating. They are the same shiny barrels underneath that are on the older models. [emoji6]
Haven't seen for sure why the coating, I've seen reasons from a rust preventer to a reflection preventer. Either way just remove it.
There's a few threads with different ways to do it. Some lightly sand it off then polish, and I think most have used a stripper (like you would for the frame) to remove the coating. Then polish up with Flitz or some other metal polish.