There are definitely black GC3s... lots of threads here on AZB about them. Typically they are glossy, "piano" black.
Black GC4s are typically matte black.
Interestingly, I've found some pictures of GC4s that had no head rail badge, like this one in the pic. But GC4s have stamped logos in the corner pocket casings, and flush-mount pockets, while this table has neither of those features.
So, I'm thinking this is either some kind of hybrid GC3/4, or maybe a knock-off, or maybe someone refinished a GC3 and removed the head rail badge.