Some folded in mylar and some rolled with poly and put into a tube. As said, the plastic keeps the ends from crushing.
They rolled ones can be a bit of a pain to store and handle. It's worth it, though.
Whatever little additions that can be used to prevent physical damage when handling and storing, is a good thing.
All it takes is one bit of bad handling, and something that has survived 70 or more years could be reduced to a piece of rubbish.
