Works for baseball bats. I see no reason why it couldn't for a guitar neck. Though I, too, have never seen one.
Ash, black - 540 kg/cu m
Ash, white - 670 kg/cu m
Maple - 755 kg/cu m
Mahogany, Honduras - 545 kg/cu m
Mahogany, African - 495-850 kg/cu m
Disclaimers: I'm happy to share whatever relevant gear knowledge or experience I have. Genuflection/payment/proof of worthiness neither sought nor accepted. I don't design, build, market, sell or endorse for pay any new music product or service. I occasionally sell personal used gear. I am an unpaid endorser of SoundScaper Productions and Godfrey Daniels Guitarworks.