Raimey,
The proof marks themselves are Federal Republic of Germany marks and are the same for all proof houses at the time. The house mark for Eckernfoerde was the oak leaf, the house mark for Ulm was a stag ( Red Deer) antler. I didn't see the Ulm house mark on the gun. One of my drillings passed through Ulm for a post war reproof after rechambering and the font seems smaller, but the marks are otherwise the same.
Mike