Of course that plating was originally used because of its natural oxidation process protecting the bare steel from a much more rapid deterioration. This was all about a cheap mass production method to prevent the steel from rusting. However these plating's were never intended to be a long term decorative finish. I'm not saying it's a bad thing to polish one up, I'm just not too keen on it being an historically accurate process. Probably the only person to have ever see that chassis so shinny, was the factory worker that pulled it from the plating tank.