Not seen them personally, but a buddy of mine has them on cams in the unit. And quite a few south of there too, as far south as the Umtanum. I think they have now infested 2/3 of the state or better.
My neighbors up Olalla have heard them at night. I'm just waiting to get them on cam up there. Have heard from a few guys that they have seen them or tracks all over in the unit.