He lived in Dickenson Co. for 23 years. Can we assume that he is 23? No. He was sentenced to 18 years in prison. He served 13 years of the sentence. My wife reads it "...13 years to my 49," which means that he was 49 when he got out. She says that is a common way of stating age and time in the region. (I would guess that he was 13 when he moved to Dickenson Co.)
Dickerson is common in the southeast for Dickenson, and that is how it is pronounced in the song.
Stanley said that the song was made up by the man who served the time (name not mentioned in the interview- still alive when the song was recorded by Stanley?). The rough edges have not been smoothed and Stanley probably left the grammar alone (unlike Allison Krause who polishes so much that the feeling sometimes is lost).
I have put the song on my desktop until I can get it all. I had a little trouble understanding that the jury came in on "Monday." There is a lowkey complaint in the song- He was tried in Buchanan Co. for a crime done in Dickenson Co. The sheriff was outside of his territory. We never learn why the sheriff was shot.
It would be interesting to find out the date of the crime and look for anewspaper reports. I also wonder if another singer has taken up the song yet.