Here's an article I published on my site back in December 2016 when he sent me the coins (picture included):

Defcon23 - stylish and tremendously cool physical Bitcoins - 0.5 Ometeotl gold and silver 2016

https://nandibear.com/defcon23-stylish-and-tremendously-cool-physical-bitcoins-ometeotl-gold-and-silver-2016

https://www.nandibear.com/blog-img/defcon23-physical-bitcoins-ometeotl-gold-silver-2016-nandibear.com.jpg