If you booked far enough in advance, they mail the DME package approximately three weeks before your trip. If you haven't received them before you leave, you can still avoid baggage pick-up and describe your bags at DME check-in and they'll still retrieve them for you.
We went in February without having received tags and it went smooth as silk anyway. I took digital pics of our bags before we left and printed them off. The CM at check-in was very impressed and it made it a lot easier to process us through. If you don't have a picture, they have a large chart of every imaginable shape and design of bag, find yours on the chart and you're good to go.
Have a great trip! :sohappy: