Yes and no. Undergraduate school recognizes MLK day through a week of activities but does not cancel classes on that day. The law school does, I assume, participate in those activities and it cancels classes on the holiday. And at the risk of stating the obvious, MLK day is a federal holiday recognized in all 50 states and D.C. Confederate Memorial day is not a federal holiday, has no single month in which it is celebrated much less a single day, and is recognized in only 11 states. D.C. is not one of them.
Of course my original question was whether a school more aligned with non-Southern traditions be expected to accommodate student requests at variance with the status quo.