Or smaller
Of course, the actual RCS of the B-2 is one of the closest guarded secrets we have. Rumor has it the B-2 RCS is less than that of a small bird. Rumor also says the F-117 RCS is on the order of a BB. Rumors aren't always accurate, but it'd be nice if they were in this case. Odds are we'll never know. The top speed and altitude of the SR-71 still hasn't been declassified even though the plane has been retired for 11 years.