if it's stainless then I'd wager 420HC, if not then I'd say 1070 or better, just based on some internet research about 'Soligen Steel'. Looks like Krug and Priester makes guillotine and stack cutter blades, which would mean a lot of pretty high pressure cuts through lots of paper, some of them very thick stacks. I'd bet you could get a good knife out of them for sure - I know I'd try it.
If you have enough to play around with, take a smaller knife sized piece, normalize it a couple times, then heat it and quench it (even water quench would work for the test). Then stick it in a vice and smack it and see if it breaks or bends. I'm betting it will break, and that the grain will be nice and tight if the normalization worked well.