Check this out: http://www.ebay.com.au/itm/Custom-6-...aad4475&_uhb=1
Is it me, or does that bass have no truss rods, despite the description saying that it has two? There's no cavity/opening for one at the nut end of the neck, and there also isn't one around the heal of the beck. This bass is a set-neck construction, which means that you can't remove the neck at all, let alone to access a "hidden" truss rod.
So, that means that the description is inaccurate, and that the bass has no truss rod(s), which is never a good thing construction/design-wise. Also, the top of the pick-up cover looks like it was coloured in with a felt-tip marker (though that might just be me being mordant).