I guess we all know what we have been told in family lore. As historians we must keep an open mind about family lore, especially about things that happened 150 years ago. In my own family, it was passed down that the original Ross of my line that came to America was on a ship that was attacked and sunk by pirates off the coast of North Carolina, and that he was set adrift and barely escaped with his life. Cool story. Historical records, however, show he came ashore in Pennsylvania, all safe and sound. The history of the ship he came in on is documented, and it was not overrun by pirates, but broke up on shoals on the east coast during a storm. Darn!

We know what we know. Sometimes what we know is incorrect.

Your ancestor, Pinkney L. Powers, was a pretty famous person in southeast Missouri in the latter half of the 1800s. He is very well documented. In your post, you seem to be under the impression that the person who wrote that biographical sketch is alive and kicking and walks among us today. However, he is long dead. His name was Henry C. Wilkinson, and he served with Pinkney L. Powers during the Civil War. He was well acquainted with Powers. He did not "document a long deceased" person, as you say. He document a man who was his neighbor.

The Missouri State Archives in Jefferson City maintains extensive records on Union soldiers from Missouri. What they have on Powers shows us that Pinkney L. Powers mustered into Company H of the 47th Missouri Infantry on Sept. 9, 1864, and mustered out on March 29, 1865. The Battle of Pilot Knob was September 27, 1864.

The Missouri History Museum in St. Louis has a file on Pinkney L. Powers. It has a number of letters that were sent to Powers in 1865, including two letters from his wife, Elizabeth, that were sent to him on January 12, 1865 and February 8, 1865. The file has a letter from his sister Matilda Cobb that was sent to him that was dated February 8, 1865. There are other letters to him from other acquaintances, including from F. M. Young on February 6, 1865; John Atkins in January 1865; Benjamin Pew on January 4, 1865; and two letters from William Wilson sent to him on January 12, 1865 and January 15, 1865.

In addition, Pinkney L. Powers shows up in the 1870 Census, the 1880 Census, and the 1900 Census. (I suspect he was also in the 1890 Census, but as most active genealogists know, that one was destroyed in a fire in 1921.)

The National Archives maintains Pinkney L. Powers' military file, and his pension file. Both establish that he did not die in 1864, but lived to be an old man on into the 20th Century.

With a bit of research, you will find that Pinkney L. Powers, a legend in southeast Missouri, died February 7, 1901, not at the Battle of Pilot Knob in 1864.

You say you have no reason to believe he did not die in September 1864. Perhaps you do now. And dog gone it, I sure wish that story about my ancestor having been set adrift by pirates had turned out to be true too!