Found this Tom's yesterday from Spartanburg. I don't think I have ever seen a 12oz. Toms, although it may be quite common, I have never come across one.
Kari seeing as it's an embankment you might try the very top. It's odd but I read elsewhere that the oldest bottles were found there. Of course both Danny and I go with the philosophy that they would roll to the bottom which could be true for this spot. I too agree that you need to keep going down to see if there are older layers of dumping at sed spot (hopefully so) and not somewhere completely different. Good luck digging!
I found an early 1900s medicine bottle--round-- at the top of a hill. But at the bottom, GodsChosen, was a rectangular medicine bottle. That should have been reversed. So, I would say location doesn't matter. The one that should roll didn't, the ten-years-later-one seemed to. Or was just thrown down there. Let me tell you, that was an incredibly steep hill. I'd say start at the top and work your way down. Also check in the water. Never know what's down there. You see them that I aforementioned.