Actually, it all depends on whether or not the boundary wipes away the FTL memories/selves of ONLY those who were cursed, or if it wipes ALL magical/FTL memories/Selves away. So August may not be able to leave town- what if he lost his memories of WHO he ‘really’ is- Pinocchio.
Another thought is Gold hasn’t told anyone at this point (In fact he has flatly REFUSED to at least twice), that he has a son, so there is no way he’ll say jack about Bae to anyone (other than maybe Belle), so I doubt he’d have told August about him at all.