Hello Mario and Chris:
The height of the eagle and the non-voided area between the wings and the legs lead me to believe the Wappen may be circa 1887 or earlier (perhaps it has been painted). I have also seen conventional M15 spikes on Juncker Kürassier Metallhelme before, though I have no idea why. Despite the questions, $1000.00 would not be an outrageous investment.
Chas.