hello Ken,
Series I & II instruments generally have a hollow core; this was true back then (the 70's) as it is now. You can choose not to have the core hollowed out, but that's a customer request; even then you still end up with a fairly hollow bass just because series electronics require a lot of real estate. I've had my last 2 Alembics made with a hollow core, and it's a feature I like in terms of the weight it saves. I also suspect that it may make the sound a bit deeper but that's harder to tell, as my basses have different shapes, woods & electronics and comparisons are not easy . But I would not say that it's an obvious influence on the sound of the bass. Outside of any electronics, the neck woods, top wood and the wood you select for the body will have the most impact on the sound.
Valentino
