The Gibsons, at least the later ones, have Corian nuts.On the question of nuts, if you're paying Gibson prices you would expect a properly cut bone nut. The cheaper more mass produced Epi will likely have a synthetic premoulded nut in a colour which matches the rest of the hardware, or in the case of the PRO IV and PRO V, a brass nut painted black.
That photo helps a lot. It confirms that yes, the bass was inspected and that it was made in China and most importantly - that you shouldn't throw it away!