Well, a proton is UUD and a neutron is UDD - so the interaction would have a UU and a DD pair. the UD combo I dunno about. I suspect that it would absorb a bit of the energy of the pair annihilation and end up as a UD and a DU meson/antimeson pair, which might or might not have sufficient kinetic energy to leave the scene of the crime.
It would -not- be as strongly preferred an interaction as a particle/antiparticle pair.