I am really not even close to a wood expert but had been under the impression that good horizontal and vertical grained boards are typically quarter sewn.
I have an old billy white hustlin hen that has some cathedral in the wood that's pretty noticeable toward the handle end on the base of the call if you are looking at the call from directly above. And of course that's a good call.
Can a good call be just as likely quartern sewn as it is to be flat sewn?