Bill,

Yes, the vast majority of the time, the fly makes the difference. Based on my experiences in times with two of us fishing out of the same boat and/or changing flies then getting hits, yes the fly makes the difference. There are rarer times when they will hit on almost anything. Naturally this is based on presenting the fly the way the fish wants it (depth/strip/etc). If the fly isn't presented properly then nothing will hardly work.

Larry ---sagefisher---