You have to ask for them. They keep then in the cooler. They cut them up into small packs portions and sell them that way. They never put whole uncut racks out for sale.
Thanks Che,
If Sam's Club sells the cut up versions of short ribs in the meat department you can ask the butcher if he will bring you out uncut racks. They sell them about 70 cents cheaper per pound that way but never set them out to sell uncut.