Hi, Jim V. and folks,
The first adoption of the Luger by the German armed services was the Marine Modell 1904, but it was in 9mm, not 7.65. (Marine means "Navy"; AFAIK Germany had no Marine Corps as we know it.)
I do hate to get into this, but the "red nine" grip shown has the "9" much higher on the grip than pictured in the books, and the grips look too new for a WWI vintage gun. There have been reproduction Luger grips with the "9" sold and these do crop up from time to time.
Jim V., yes, Stoeger has the copyright on the name "Luger", which is how they were able to put out that POS .22 a few years back with the name "Luger" on it.
Actually, "Parabellum pistol" is used in Europe, where the guns were never called Lugers. "Parabellum" comes from the Latin phrase "Si vis pacis, para bellum" (if you want peace, prepare for war) and was used by DWM as their telegraph address, from which it was applied to the pistol as well as the Parabellum machinegun.
Jim