Dave,
I will try to answer the questions.
Sometimes we see daggers having such an amount of "wear" on the eyelet of the hanging rings. In many cases these huge ones were applied by the wearer to adjust the angle of the dagger and/or to avoid movement while being worn.
Brass is a metal alloy made of copper and zinc. The verdigris we see is normal on uncleaned pieces. Usually the handle has more of it because it's there were it is not easy to remove and it's the place where the hand of the wearer rests in most cases.
The configuration of the dagger parts is what I would expect. Especially the missing buffer plate and thick leather buffer is a typical configuration for WKC pieces of the early 1930's, the manufacturer mark is also correct for this time.
What strongly speaks for an untouched dagger is the sit of the Portepee. One can not fake that. This is true age patina, if one would try to remove that Portepee it is impossible to re-attach it. Most likely it would break on some areas, but even if not, it will never be the same.
I agree that every collector should have his own opinion, but in this case I believe - and indeed it is nothing more than a believe - that we are looking on a nice original 1929 pattern dagger.
Thanks for your time, Gentlemen.
Best;
Hermann
