Was checking out NGC site as they have some interesting articles on Chinese counterfeit coins. Had a look at US coins as well and I'll be honest - they would have fooled me big time if there was no explanation! https://www.ngccoin.com/news/series/7/ Don't know if this has been covered but thought I'd share.
These aren't necessarily all Chinese counterfeits. Some are, but many are from pre-Chinese attempts. Added or removed mintmarks, alterations, and other types of forgeries have been around for a long time. The Chinese don't really do too much of this. And yes, I read each new article with interest. Paying close attention to these sorts of diagnostics and key identifiers can be very valuable.
Well heres one for everyone . I bought a NGC 1902S 10$ GOLD. It is a fake holder an coin , so i sent ngc pic's an two email's , i thought they may want to see it an study the holder. Got a reply!! Yes Mr pfg this is a fake coin an holder !! Thats it .BIG DEAL