It's believed that respondents to the O.P. never properly responded, and ignored my postings, continuing to post inaccurate information to a neophyte who asked legitimate questions, was believed scammed by false information, and falsely accused of inattentiveness on his part. The seller lied by a factor of 1000 (i.e. 1 x 10 to -3, versus 1 x 10 to -6 plating). JMHO
You could always do your own melt...it's not rocket science... Ask Google how to melt your own gold or gold plate off of vintage jewelery... A friend of mine and myself like to pick up old costume jewelry at garage sales and 2e stripe it. Sort of retirement plans.
The 100 mills refers to the thickness of the plating, NOT the total gold content. 100 mills is .01 inches.
I believe you'd find a gold coating of that thickness to be abnormal when I believe Gold can be "flash coated" to ~1/4 micron: https://www.google.com/search?q=fla....69i57j0l7.32161j0j7&sourceid=chrome&ie=UTF-8 A micron is inches: https://www.google.com/search?q=1+m....69i57j0l7.32138j0j7&sourceid=chrome&ie=UTF-8 JMHO