Dean, I am very sorry for the recent loss of your father. I suspect many of us regret the things we did not discuss with our parents when we could.
Unless the barrel has been changed or lined, your pistol is 9mm. You can confirm this with a round wooden pencil. If the eraser end slips into the barrel easily, it is 9mm. If you do shoot it, don't use hot ammo. The Winchester "White Box" ammo seems to be the favorite around here. You will probably receive conflicting advice about the wisdom of firing this weapon.
There is a breakdown instruction on this forum (
http://www.lugerforum.com/) although it probably covers a more complete teardown than you need. You might try searching the web for "Luger field strip" or similar terms.
As mentioned above, Hugh Clark (hhclark@wildblue.net) can repair the "million dollar chip" but you may want to look into buying a set of replacement grips.
Douglas, I haven't seen three digits used on a toggle either!