I agree with CDM's assessment of using a nice wand compared to a Spirit. You'd have to retool your character's charms / sockets a little to make up what you lost in terms of FHR, mana and cast rate for a level 30. If it is an incredible wand, however, I'd say go for it.
Level 30 Bone Necromancers use a pretty standard skill setup (you'll max both Spear and Spirit for the level) and both skills will (or should) be used situationally during a duel.
If these are level 18 - 29 items and you intend upon building an 18 - 29 character, then go for it as well. Necromancers are pretty competitive builds in the 18 and 30 categories.
~Hearts~