Sorry folks. A review of the complete terms and conditions yielded the following:

Room Upgrade: Upgraded accommodations at no additional charge. Based on room availability and limited to a member's personal guestroom. Not available at Marriott Vacation Club International or Horizons by Marriott Vacation Club.

Anyone else notice that the "room type guarantee" is utterly useless? One is ensured his "bed type preference," but not an "extra bed." If my "bed type preference" is "2 queens," I'm sure some tool at check-in will say "well, sir, you're not guaranteed an extra bed so we have you in a king room. The bed is soft, though, so it matches your preference." Excuse me? "You do like soft beds, right sir? It matches your preference insofar as we haven't given you bricks upon which to sleep."