On an expensive bass like any Sadowsky I'd avoid one with a neck like that and I'd want one with straight grain all the way thru. I'm sure there are those who will say it means nothing, and it may not ever become a problem. It's been explained to me by more than one knowledgeable luthier, when I faced a couple super-flamed bowed bass necks, that a dark spot on a figured neck represents a "weak/softer" spot in the wood. And that that was what caused my neck issues on those basses. I'm not one to take opinions like that as "articles of faith", but I can't dismiss it as total BS, either.
From there, it doesn't matter if that's the reality, or just another guitar myth, because there are some potential buyers who (like me) believe it to be a possible problem over time, and will pass on an expensive bass with that grain structure. So it would seem that by default, when resale time comes it may affect value by eliminating a portion of the buyer pool. On an inexpensive bass, not a big deal if the neck goes sideways. Good luck.