Thank you for your kind words and expertise Alan. I was thinking „2nd escadron“, since „DR26“ was already very clear.
However, the stamping regulations remain a mystery to me.
Following, it’s a free translation of the stamp regulation
§42,3 of the Prussian clothing regulation for enlisted men - part 1 - from 1888 (I think the Wuerttemberg regulation was similar). I don't think I have seen a helmet with the correct 5 or 6 stamps as they should be:
§42, 3 (Acceptance and stamping):
1. Stamp (Regiment): The items accepted by the regimental clothing commission will immediately be stamped with the acceptance stamp indicating the troop unit and, as soon as they have been found to be in good order during the inspection.
2. Stamp (Year): A second stamp indicates the year of inspection. In years in which there is no inspection (Musterung), the second stamp and the hand out to the battalions may take place by way of exception, but the pieces must be inspected as far as possible at the next inspection and only then put into use (§46, 4).
3. Stamp (Unit): When received by the battalions, they are stamped with a third stamp, showing the battalion's name.
4. Stamp (Year): When handed out to the companies, they are stamped with the year, as a sign that they have been put into use.
5. Stamp (Company): Finally, the pieces receive the company stamp,
6. Stamp (Garniture): and the garniture stamp (6th stamp).
Cavalry regiments and independent battalions are accordingly stamped five times.