Only if that item is confirmed to never receive a reprint ever again.
We use that order information to source how many items we should order for said item. If you don't want this to occur, place separate orders for the in-stock items and the Backorder items.
The order will ship once all items are in-stock. What happens when you place an order for a Backorder item and an in-stock item? To secure a copy (or copies) of that item at an amazing rate. Backorder: When an item was in-stock at one point and it is currently unavailable at our store and warehouse.