This photo shows a counterfeit PCGS holder on the left, and a genuine PCGS holder on the right. It is immediately obvious that the holographic image on the left holder is of poor quality and is rubbing off. PCGS has been embedding the holographic sticker in the plastic for years, although some early genuine PCGS holders have external holographic imprinting. When I asked the counterfeiter who marked the diagnostics shown in the previous photos if he would mark the reverse sides of the PCGS holders also, he said that the difference was obvious, "color iridescence hologram part no good." (Conversations with my Chinese sources usually happen via translating software, which can render some interesting terms.)
The photo on the left was first published by Random House in Scott A. Travers' amazing Coin Collector's Survival Manual, 6th Ed., which contains several large, beautiful full-color photos of Chinese-made counterfeit PCGS holders. (If you click on the photo here, it will be greatly enlarged.)