Yes, I've often thought 'I reckon the original version would have said 'XYZ' rather than 'ABC', but as you say - if the verse isn't there at all, you don't even know what you're dealing with. And I want to sing what we think the original singers sang, as a custodian of the past. I've no problem changing things to fit my voice or style, but sticking to an original lyric appeals greatly to me! What a shame they aren't really written and accessible in the same way as the bowdlerised versions are...