Simple answer is, YES. If you take a basic saber consisting of an emitter, switch, body, and pommel, and add an extension between body and pommel, you're just fine. If you buy a built saber in Warrior, Champion, or Hero Tier, professionally assembled, then the bulk of the saber threads will be sealed, except for the pommel. That is left unsealed to access the inside. So just unscrew your pommel, put the spear extension in, replace the pommel, and you're done.