The weight there is mostly from the ebony neck lams and the large size of the body. The buckeye top & back are actually quite light. If that were a coco bolo or maple bass, for example, it'd be lot heavier. Steve, at Superbass has a 4 string Triple omega with buckeye top & back and he lists the weight at 9 pounds; being a 4 string and having purpleheart instead of ebony as neck laminates reduces the weight quite a bit.
Valentino