Almost garantee there will be some, but yeah, it might be just a few, and if they only release them at the end of the day that sucks. Some shows I`ve been to however, they released them in the morning so that was good.
I personally think it`s worth to risk going to a venue without a ticket, because not only is there very often GAs (or really good seats) at the box office, but there is also often fans in the GA line with extra tix willing to sell at face value. People will often wait until the last minute to sell their extras, because they will try with friends first and so on.
Plus, if you have to resort to a scalpers, prices will be much lower the day of the show than right now.
I would personally risk driving to 6 hours to another city without a ticket. There are a few good options, but I would be prepared to pay 100$-150$ for GA if I really have to.