1) Nobody (including me) knows when they were created or authorized or whatever. A lot of information has a way of appearing, and it is my sincere hope that, like the Offermann photo showing the silver-chain in wear, more photos will eventually surface.
2) I prefer not to speculate on when they were made (of course, I like 99.9% believe that they were made before 1945 ).
3) Nobody knows the criteria specifically, just like nobody really knows how and why and when the SA Honor or SS Honor was distributed.
Regarding signatures, I wish to clarify my statement about them: it is fruitless to compare a Huhnlein Dagger signature to other period signatures on other artifacts and photos, because as my archive that I am building will show in the other "sister-thread" to this thread, every time a person signs something, the signature is slightly different. It would be ONE thing if Huhnlein's signature on the blade did not look ANYTHING LIKE Huhnlein's other signatures in the body of signatures we observe. But they do, which says to me that there is nothing inherently "bad" about the signature on the back of the blade of these daggers.
Now, if we could only find one of the "plain-bladed fakes" of the NSKK with Huhnlein signature, we could put the matter to rest once and for all whether or not they are identical or not, to the damascus-bladed examples.
Also, it should be stated that the documentary evidence that is being presented about the origin of many of these daggers is not the same as someone stating without support "Hey, I got it from a Vet."
).