Hi Kevin,
I'm pretty certain the FY-904-56 is definitely a 9' 4pc 5/6wt fly blank. I'll bet it's a brown color blank, too. That is the model number system I've seen for the import blanks that go by the name "Tiger Eye", and they are pretty nice blanks for the money. They are of an IM6 / graphite II type modulus and medium fast action generally in the 4pc.

I have a blank that was sent to me free that has the same model numbering system. My blank is the 6' 2pc 2/3wt model, and is labeled as FY-602-23 on the bag.

As for the other blanks, who knows? I'd be curious if they are all graphite, or if some of the larger diameter blanks might be fiberglass. What color are some of the other blanks, what type of ferrules do they have, and what are the lengths? Spinning and casting blanks will generally feel stiffer than fly blanks, unless they are true ultralights, so if you have a chance to give some of them the "wiggle test" it might tell you a lot. If any are spinning/casting blanks, and if they have any kind of model numbers, quite often those blanks will have a 3-digit model number with the first 2 digits being the length in inches, and the 3rd digit being the "power"...with 0 being the lightest power (like ultralight) and up to about 6 power or so for the more beastly type rods.

Anyway, I hope you find some nice blanks for cheap!