Inherited 1918 Erfurt with police holster and two mags

[OBXmom]

This luger was brought back to the states by my husband's late father-in-law around 1946 (As family lore goes). I knew absolutely nothing about guns, let alone Lugers, until I found my way here. I have to admit I'm hooked!
I have read and searched these forums, and the more I learn, the less qualifiedI feel to even post a question. I am humbled by the level of expertise represented here and will try not to waste your time.
I am confused by the double striking or mistriking of the 90 on a two places on the gun. Pictures below. It almost looks like they stamped 89 and then stamped 90 over it. Makes me very skeptical. We know it's been in a safe for the last 70 years, but before that is anyone's guess.
I've been told the vertical strap on the holster means it's a police holster, but I'm confconfusedby the unit marking P.A.L.II.409.
One magazine has a matching serial number, the other does not.
There are numerous markings, even on the grip screws.
Any input would be much appreciated.
I am still working on my photo skills but would be glad to provide more photos.
Thank you in advance for your time.
Sincerely,
Diane