I think they were referring to the quality of the counterfeit, not the inability of the TPG to catch it. Ribbit
Actually I want one of them, I have read that only a few were turned back in for the refund. And yes, those were very very high quality and well done counterfeits, purportedly made during the depression era when silver got down to 34¢ an oz, and it was profitable to make them. Similarly the Omega counterfeits of the 1907 $20 Saint were only determined to be counterfeit because the maker signed their handiwork with a small omega in greek.
I believe the 1848 small date cent was a contemporary counterfeit. I don't have a picture of one readily available but I have seen it and it is not a very well done counterfeit. I'd say they were probably made around the turn of the century. Silver was around 50 cents and oz then and there are contemporary reports from the later 1890's about counterfeit New Orleans Morgan dollars and the identifying feature that they mention to spot them is that they used "a lowercase O for themintmark." That sounds like the micro O dollars to me.