It turns out I was able to identify most of the ones without any markings by tilting it just so and seeing the impression of the markings enough to figure out what it was. Now I just have to look up those special tournament stamped discs. Thanks everyone!
On a side note, about 1 in every 10 discs was not labeled with the correct weight. If that's important to you you might want to weigh your discs. Most were only off by a gram, but some were off by 4-5 grams.