As you can hear, they play the piece entirely in the key of Eb. After a four-bar Introduction, there is a 16-bar first theme played twice through, and then a second theme (also 16 bars) played several times, always as full ensemble. The entire piece takes about three minutes and ends without a Coda. Here are the chords, as supplied to me by a banjo-playing friend.
You can hear Tuba Skinny in 2014 playing the piece quite briskly and without the four-bar Introduction (or a Coda) if you CLICK HERE. They make the tune last four minutes, with much soloing on Part B.
More recently, I have seen the original sheet music. It was entirely in the key of C. It too began with a four-bar Introduction, not dissimilar to what the jazz bands play. And it too had a first theme of 16 bars, with a pattern very like the band version, and even including the attractive and distinctive diminished chord arpeggio in Bars 13 and 14. Then comes the second theme of 16 bars, which is very closely followed by Bunk and his imitators. Finally there is another theme of 32 bars, much in the spirit of the earlier themes. No jazz band, as far as I know, plays this third theme. Ever since Bunk, bands have decided that the first two themes give them enough to work on.
Dusty Rag was composed in 1908 by May Aufderheide of Indianapolis. This remarkable lady was only twenty years old at the time. Her proud, wealthy father set up a small music publishing business to sell her sheet music. Dusty Rag became very popular and she went on to compose many more pieces. One of them was Thriller Rag, which is also still played by our bands.
May Aufderheide lived to a good old age. She died in 1972. So she experienced the entire early evolution of jazz from Buddy Bolden until long after the death of Charlie Parker. Amazing to think she was still alive to hear The Beatles' recordings of A Hard Day's Night and Sergeant Pepper's Lonely Hearts Club Band.
She lived through nearly three decades of my own life. How I wish I had had the chance to meet her and talk about those early days, and what she thought of Bunk Johnson's and Ken Colyer's versions of her music.
Here's May Aufderheide's composition. It was orginally called just Dusty, as you can see.