Resurrected after less than ten years. :)
I had to really reduce heavily to get this under the 300K limit:

The first stamp is genuine IMHO.
The next four are all with a smaller design, and all forgeries. These are easy, especially that first one.
The last three are tougher. Note the design of the shield for the Hussar. In the genuine it's formed by two diamonds in outline. In the three forgeries the design is either not there at all or very different from the genuine.
I don't have enough examples of the second set (1921) or the 1921 overprints to show a representative sample of the forgeries. I believe they will follow the same characteristics as these, however.
If anyone has enough of these issues to find more types, please let me know...