After re-reading the articles by Wiley, I'll have to admit I was in error on one point. There are 15 die marriages of the 1861-O, but one of these is indeed the one with the CSA reverse, of which 4 coins are known to have been minted. Condor101 was correct, as he always is! Excerpt from the article I have by Randall E. Wiley: Die Marriages of 1861-O Half Dollars By Randall E. Wiley "A 15th die marriage is also shown in the figure. This marriage is shown as marriage #12 in the emission sequence where obverse 5 was taken from the normal coin press, paired with a uniquely prepared Confederate States of America (CSA) reverse die for the striking of four specimen coins on a special screw press, and subsequently returned to the normal coin press reestablishing its original die pairing with reverse E."