Thanks, Lighter, for calling my attention to the Lomax volume. The versions are different. The Lomax version first appeared in 1938, in "Cowboy Songs and Other Frontier Ballads."
Ohrlin gives no date for his collection (He sings his version on the Max Hunter website). Laws apparently mentioned the 'Brennan' version in 1957, but I don't have the reference.

It has little relation to the bloody Missouri-Kansas feuds and guerrilla campaigns of the Civil War period. Posts here show that to Union supporters Quantrill was a killer. To Southerners he was a hero and patriot.

'Charlie Quantrell' was just a highwayman of English style.