I googled the WM code, and it indicates Whitman AFB. (The base web page says the 509th and their B-2's are based there) So that makes sense.
Perhaps this particular B-2 had some work done recently and the code was not reapplied?
I would presume that it is the same B-2 (Spirit of Hawaii) if the 90-0041 matches. They only built a handful of B-2's to begin with.