Here's how I learned it. I've been told it is close to how Woody Guthrie sang it, although I never heard his recording of the song.

I'll sing you the story of Billy the Kid,
And tell you of some of the bad things he did,
Way out in the West when our country was young,
When your gun was your law and your law was your gun.

The Mexican muchachas loved Billy so well,
How many he had nobody could tell,
With a cute señorita he came to his end,
Shot down by Pat Garrett who once was his friend.

Pat Garrett rode up to the window that night,
The sky it was clear and the moon it shone bright,
Pat listened a while while the Kid told his tale,
Of killing the guard at the Las Cruces jail.

While the couple made love Pat waited outside,
Then Billy he said, "I ain't satisfied.
There's twenty-one hombres I've put bullets through,
And Sheriff Pat Garrett will make twenty-two."

Then Pat Garrett fired, his thumb buster cracked,
And Billy plumb naked was blowed through the back,
Pat rode away, left the Kid lying dead,
And that's the way Billy was killed in his bed.

So I've sung you the story of Billy the Kid,
And told you of some of the bad things he did,
Way out in the West when our country was young,
When your gun was your law and your law was your gun.