That reminds me that I really need to buy a copy of Harwood's book.
I found the following early text on his website which makes the cannonball confusion clear, it is indeed gambling house brawl in this version.
"Old Time Gambler's Song" - St. James Infirmary in 1926.
Lyrics to "Old Time Gambler's Song"

This text was sent by Terence McKay to Robert Winslow Gordon in a letter dated April 5, 1926

Old Time Gambler's Song

I dreamed I went down to St. James Infirmary
Thought I saw my baby lying there;
Laid out on a clean white table,
So pale and yet so fair.

If she's gone, let her go, God bless her,
For she's mine wherever she may be;
You may search this wide world over
You'll never find another pal such as she

I may die out on the ocean
Be shot down in a gambling house brawl;
But if you follow me to the end of my story
You'll find a blonde was the cause of it all

When I die just bury me in a box back suit,
Blue shirt, roller hat, pair of shoes with toes so tall;
Put whiskey in my coffin, deck of cards in my hand;
Don't let them weep and wail, don't let them moan at all.

Put marihuana in my coffin,
Smoke it as you carry me along;
Take even rolling crap shooters for pall bearers,
Coke sniffers to sing my funeral song.

Put a twenty dollar gold piece on my watch charm
So the boys'll all know I'm standing pat;
Put ice on my feet, for in that place where I'm going
I won't even be cool with that.

Just carve it on my tombstone
In letters bold and black,
"Here lies an old time gambler,
Pray God won't you please bring him back!"

From "Songs of the Cowboys" (1966) by Austin E. and Alta S. Fife.

The references to marihuana and coke sniffers are interesting, looks like this bit was tamed down for the later commercially recorded versions.