To follow up on Dr. Fey's article in a recent Curry's Chronicle, I came across this article from About.com that was posted on Vamworld.com that discusses some diagnostics of the fake slabs. The interesting thing about this article is that the fake slabs, and I presume, counterfeit coins, are the 1876-CC Doubled Die Reverse Trade Dollar and an 1876-CC chopmarked Trade Dollar.
coins.about.com/od/coingrading/ig/Fake-PCGS-Slab-Diagnostics/