The best site on the net for identification of pickelhauben is: http://www.kaisersbunker.com/
I have used this site to keep my own thoughts organized. Some of these links may help. I have been evolving a lot in my belief and understanding of helmets. In general there were private purchase pickelhauben and issued pickelhauben. All of them started out with some sort of producer. In the private purchase world itseems that you could buy anything. There were several levels of goodness in a helmet and issued helmets had to be purchased from a supplier. The big differential was cost and quality. I have not yet written the article I need do on this.
I have a base issued helmet here:
I have a base officer helmet here:
I have an article on one-year volunteer helmets here:
I have a timeline of pickelhaube development here:
I have some information on wappen here: