I agree. Although, I've seen that sort of thing in the past on old better-made pieces of furniture. I think back when curly Maple was more plentiful than it is now, some of the craftsmen may have thought if it wasn't 5A, it was construction grade. Actually, I'm not sure how long the various "A" ratings have been around. They may not have started grading it until it got a bit more sparse. It was either regular ol' Maple, or it was "fiddleback" - the super-figured stuff used to make violins, that today we would call "5A".