Well, it certainly began life as one of these:
It is the Ersatz helmet Joe refers to as a "kit helmet" because the individual parts snap together. It is also known by the term,
Eisenblech. The same type of helmet is pictured in Larcade Volume I on page 113 (No. 8; with the Baden griffin). But, this much I believe you already know.
As for the spike, the base, with it's faux domed retainers, is the same as the example on my helmet. My best guess is that the spike had been irreparably damaged, someone cut it off straight, and plugged the hole with a dowel.
I'm not convinced the Grenadier Adler is original to the helmet as it does not fit particularly well and there is no photo of the attachment loop. Those who have handled one of these helmets know it is secured by a wooden dowel passing through single horizontal brass tube (like a door hinge).
There is no trick to taking clear, focused pictures of a helmet. Poor pictures like these are almost always dishonest, and meant to fool the unsuspecting bidder.
