Joe, MMario gave that same link way back in the 2nd post in this thread. It confirms what I've read elsewhere, except for its allegation that Dill was the composer of Streets of Laredo, an allegation that has been laughed out of court elsewhere on this thread.

I read on another site the author's opinion that it was the greatest country song ever, and that one of the things in its favor is that it's so great you can't sing it badly. Then I looked elsewhere and saw folks suggest Johnny Cash sang it badly, Joni Mitchell sang it badly, Joan Baez sang it badly, Lefty Frizzell sang it badly, Mick Jagger sang it badly....

Anyway, I think the preponderance of evidence is that it's correctly attributed to Dill and Wilkin, circa 1959.