Coincidentally, my new copy of David Brody's excellent publication, "The Fiddler's Fakebook" arrived this morning. I quote from his preface:

The tunes which follow are not to be taken as the "right" or the "real" version. An application of these terms to a musical genre so wonderfully capable of change and variation as the fiddle tune, that chameleon in binary form, is to misconstrue its nature... In some sense all aural music is improvisational. You only begin to internalize the possibilities of variation and improvisation in a given style through repeated listening.

In other words, use your ears as well as your eyes. This is one of the subjects twittered over ad nauseam in TheSession forum - dots or ears, ears or dots. Using both makes sense to me.