The tune for Humping the Drum is from the old Irish tune, Eibhli Ghail Chiuin Ni Chearbhail, (Sweet & Gentle Eibhlin O'Carroll). I sang it at a sesiun in Ireland back in the 1990's and one of the fiddle players, who knew the tune, joined in immediately. It would be fair to say that the tune travelled across the World faithfully, all those years ago. John Martyn recorded a distorted electric guitar version back in the 1970's.
The lyrics from 'Peace' and Bob Bolton are both legitimate from my experience.
I recorded this track, under the direction of James Griffin, for the ABC back in the early 1990's on an album called 'Going Home'.