Well I heard this too, but pecker said he knew sullivan john, and wrote the song about him. Its a absolutely brilliant song, without a doubt.

Who is this mysterious 'somebody else'?
Normally, if someone claims they wrote a tune, or song they are going to make a fuss about someone else claiming it. Isn't that right?
No, I think it was written by Pecker, until someone   stands up and say 'NO, I Wrote it' this is when, where and why. [ failing that someone who says; xxx wrote it, here's when where and why.]
All this Pecker has done. who else has? And why would a man such as pecker claim something as his own when it wasn't? For what reason?

On the road, as in any area of life there are good and bad. Life is rougher, but the rewards are priceless. A man lives on his wits and is judged by his word.