I BELIEVE all the information cited is accurate in the Jewelry industry. I do NOT believe pen making companies are bound by those same definitions.
In short, I doubt we have any idea what is in the plating.
Ed.I think that any entity or company that advertises any precious metal Karat or Purity content that it MUST COMPLY with international law, There used to be an issue with Sterling silver when the newer anti firescale alloys were introduced, traditionally the Sterling alloy was 92.5% pure silver and 7.5% pure copper, There was a lot of confusion as to the addition of Indium and several other firescale inhibitors was introduced. It took the FTC almost a year to issue a ruling which was as long as the piece contains 92.5%pure silver, Excluding Solder, then it can be marked and sold as Sterling silver. So bottom line is no one is exempt from the Karat designation . of course as long as there was .916% pure gold the rest could be what ever they wanted to put in, all kit would do is alter the color.