No, readers do not receive a notification that they have won a drawing. Rather, there will be a new reward listed as "Raffle Prizes" on their reader page that is available to be redeemed.
Something called "Raffle Wins" appears on a reader's page when that person has won a raffle/drawing. The reader does not get notified of this. Rather, if they have been notified in another way and come in to claim their prize, branch staff may mark the prize as having been claimed.