There was a popular bluegrass song about Duncan and Brady just recently. “He’s been on the job too long!” is the line that sticks in my mind: that would be the sheriff/marshal, I guess.
Brady, why didn't you run?
Brady, you shoulda run.
Brady, you shoulda run,
When you seen Black Duncan with his Gatling Gun.
When all the girls heard that Brady was dead,
They went downtown and they put on red,
Marchin' down Main Street singin' this song,
'Brady's struttin' in Hell with his Stetson on.'"
- that's all I remember of the song. It's in Carl Sandburg's American Songbag, which unfortunately is sitting on the bookcase by my piano while I am at my parents' house in SGA.