No expert, but different species of wood with the same type of flowing grain are called different names in certain wood. Most of the time "tiger" is referred to maple, fiddleback to walnut, birdseye (possibly caused by fungus)to sugar maple (hard maple) although have seen it in pine and some cherry, and is seen in birch,(yellow) and walnut.
Quarter sawn wood gives another view, especially in white oak. A lot of Victorian furniture is made in quarter sawn white oak.
A lot of your Pennsyvania long rifles were made from curly maple.
As far as being valuable, it is all supply and demand. Most of your good gun stock wood with crazy grain and figure is from the crotch of the tree or down near the base, or root. Drying this wood is difficult because the grain is running different ways and it's hard to stabilize and dry without cracking, so the price goes up also.
Was at a lumber shed years ago and saw a piece of fiddleback mahagany, bought it for the regular price of mahagany and made a nice 5'x 18" side table from it. You can actually feel the waves in the wood. Don't know how the planer didn't rip them out.
Post some pictures when you get it, it's always nice to see great wood.
