"We've seen these on occasion," Spiegel said March 21 via email. "Both the coins and holder parts are counterfeit. The quality of these counterfeits is generally quite poor. For example, the $50 Gold Eagle is labeled MS 70 but looks like a PF coin (and does not appear to have a 'W' Mint mark).
"We encourage people to always check the Verify NGC Certification feature on our website (https://www.ngccoin.com/certlookup/). Since October 2008 we have imaged nearly all of the coins that we have graded as a measure against counterfeiting and tampering. You can compare a potential purchase to these images to make sure that they match. In the case of the images you sent, they do not match the ones we have available on our website.
"If a legitimate NGC certification number is copied on a counterfeit holder (or if there is some other issue related to that certification number) we will put a note 'Contact NGC Customer Service' in our Verify NGC Certification tool to advise a prospective buyer that they should contact NGC Customer Service.
"We are researching both the origins of these counterfeit holders as well as enhanced security features for our holders. Counterfeit holders not only infringe upon our registered trademarks, but also violate the Hobby Protection Act of 1973 and the Collectible Coin Protection Act of 2014. We will consider all available options to pursue those who counterfeit our holders."