That’s not going to work, that’s just going to give you the volume, not the weight, you would also need density and mass to make the appropriate calculations, and whilst volume by itself would be an interesting area of bass research, it’s not going to help those wishing to lighten the load.
You would get better results by incinerating the bass and collecting the resulting gasses in an atomising spectrometer, which would provide accurate measurements of all the bass elements which went into the manufacture. This would then provide the most accurate weight measurement of the guitar.
However it may prove difficult to sell afterwards.......