I feel most of the ferrule material out there is not strong enough to hold up without capping it. Fiber ferrule material was nice uncapped, but that material is history now. Some linen based materials hold up uncapped, but I feel it is most often just a gamble to put the hole all the way through.
ivory, imo must be capped. but i'm using a lot of buckhorn, elk horn, moose etc and i like uncapped threaded the best. this is only a 6 month experiment, but so far no problems. chuck starkey