Was skimming through the book, Quill Gordon by John McDonald last night. Gives a good overall history of fly fishing going back to Dame Juliana. I believe that I saw that the terms 'gaudy'/'fancy' were used and defined in relation to a type of fly because of the way it was dressed. They seem to be synonymous for 'attractor'. I think the description in McDonald's text was taken from the writing of Skues.
Maybe it would be interesting to see specific examples/references of how some authors actually use these terms in the context of their articles or books. Like 'Bob' wrote above, maybe its a matter of the regionalization of magazines and authors?
Just sayin