Crabs, haven't grown/sown them, but from what I can see once the nuts are released from the bur, there isn't a need to do anything to the individual shells/seed coats. There is, though, plenty of information that suggests these dehydrate very quickly after ripening in Fall and unless stored moist or planted will lose their viability.

If you were asking for the procedure too, I didn't include that -

hort.harvard.edu
Sow in Fall for the reason above. Or place in moist cold storage immediately after Fall harvest, approx 32-40F for 90 days. Following, transfer to warm sowing medium, placing nuts on their sides about 2" deep. Some may begin to germinate prematurely in cold storage.