Would be a nice project to find the mag(s) with SN 9799
Then you would have an matching 1916 DWM with matching mag- that would be a fine addition to the family treasure! Follow that with a period correct holster..... There's a listing of "orphaned mags" somewhere in this forum I believe- just for that reason...
I'm sure the owner of the 1916 DWM with the same SN as those SN's on your mags would be interested in your numbered mags to match up with his / her gun? That's why in my signature I have written "Looking for mag # 7097"
My father found an 1863 flintlock musket in his father's attic- which, of course, is in our family. I ended up restoring it.... found a bayonet, the proper flint, a sling, some inner parts... and learned all about that firearm in the process. Talked to experts in the field... I had no idea what I was getting into- and I had great fun doing it!
Very likely your Dad would be proud to see you put together a special rig with the starting 1916 P08 SN 9799.