Sure, and in several theories of gravitation where there are gravitons as an uncharged massless spin-2 gauge boson (General Relativity isn't one of these; it doesn't have any gravitons at all, although the non-quantized classical gravitational waves have spin-2 symmetry) then gravitons are their own anti-particles, just as photons (uncharged massless spin-1 gauge bosons) are their own anti-particles in the Standard Model.

(i.e., anti-gravitons and gravitons are the same thing, just as anti-photons and photons are the same thing).

There are a variety of other theories of gravitation with gravitons, but as far as I know, there are none in which gravitons are not their own antiparticles. (There may be such theories available in universes with a very different cosmological constant or with different numbers of dimensions than the one we are in).

I love groups who, while considering something as crazy as time turning into a physical direction as it does in a black hole, can still manage voting down someone down thinking outside the box.

I like the idea of anti-gravitons being the inside of a graviton, or inside of a black hole. Given the inside of a black hole is essentially the end of time, coming out of a black hole or coming out of an anti-graviton, could equal going back to the beginning of time.