I
think I may have found him. On
https://segtours.com/blog/archives/2454, there is a list of veterans who attended that reunion. It was unexpectedly long--but, among the names, is O. Richard Gellette whose address at the time was in Shrevesport, LA.
View attachment 407509
Dallas Morning News (2 June 1944)
It's hard to hear clearly but I think that the film's interviewer referred to him as "General" at one point.
According to Billion Graves, he was born 23 Sep 1845 and died 1 Jun 1944; he is buried with his wife in the Fillmore Cemetery in Haughton, LA; his gravestone says he was a
major general. He isn't going to show up on HDS/Civil War Data because none of the 2nd Miss. regiments (there are several, both state and CSA) have a roster.