I wouldn't blame Christy Moore personally. It's never clear what the intentions are when someone claims "new words." In some cases, it may be an attempt to secure copyright on one particular verbal formulation; in others, it may simply be a way of acknowledging that the source is not being followed to the letter. In other words, it may be a form of hyper-honesty rather than a form of dishonesty.

In The Christy Moore Songbook, and in many other places, Christy has acknowledged Reilly as essentially the sole source of the song.