You will not need your member card for anything on board. In my 10 cruises I have never been asked for mine.
You may want to stop by the DVC desk on Deck 4 on your first evening, just to make sure they have you on their "Mambers-On-Board" list. Even though you are not cruising on points you will still get lots of goodies in your stateroom and, as mentioned, they have a member meet one day.