The 1991 third edition of the Van Allen and Mallis Comprehensive Catalog and Encyclopedia of Morgan and Peace Dollars ("VAM" book) includes a table (p.406) listing the dates and mints known to the authors to have been included in the Redfield Hoard. The 1879 minted in Philadelphia--relatively common among Morgan dollars--is not among the listed dates, although "many" or at least "a couple dozen" bags each of 1889, 1890, 1896, 1897 and 1898 Philadelphia coins were included, as well as smaller quantities of 1892, 1893 and 1903. The NGC registry set for "Redfield Holders, Morgan and Peace Dollars, 1878-1935, Including Varieties", includes slots for several date and mint combinations not in the VAM book table, but none for an 1879-(P).
Ronjovi may have a stray, unlisted coin--perhaps a discovery specimen--that would be of interest (and possibly a high price) to a specialist in Redfield holder coins. He may also have a coin in a holder that is counterfeit or has been opened and another coin substituted for the one placed in it. (While the coins in the vast majority of Redfield holders don't grade "MS 65" by today's standards, this one, featuring a huge obverse scratch, seems inconsistent even with these looser 1970s standards.) Perhaps he should submit it for NGC certification--I don't think PCGS grades coins in Redfield holders--and see if it authenticates as a Redfield coin.