I used to plug the ends of cane shafts but don't anymore. I found it is not necessary. I cut in self nocks and add a wrap of sinew(thread will work too) and have never had a failure. I also use glue on points(commercial), trade points and stone points without plugging the ends. The sinew wrap takes care of that too. With glue on points I do use my belt sander with a taper jig to make the taper. I never had luck with the pencil sharpener type taper tool with cane shafts. Others may.
Everyone has there own way of doing things and there is not necessarily a right or wrong way. If it works for you then do it.