That 1872-S Half Dollar looks too nice to be only graded AU-53. I wonder what was going on the grading room when that happened? And yes, that is a darn frightening counterfeit. I saw something similar in a holder at the Philadelphia EAC Convention a couple of years ago.
Also, unless there were two different styles of "S" Mint Marks used for the 1872 Half, the mint mark on the counterfeit is smaller and a different style than used on normal 1872-S halves.
Are you referring to the discussion or to the half dime itself? I just checked eBay, and the half dime is still available as a fixed price offering. Regarding the discussion, I remain unconvinced that the coin is genuine, but there still seems to be some sentiment that it may have been struck from a second die marriage. I have seen no images of a different obverse die for the 1864-S that would sway me.