1912 Erfurt #4458

[HH]

I need some expert help. I was given a 1912/1920 double numbered Erfurt, serial # 4458. All of the numbers match except the clip. It appears to be in good condition. It came with holster and take down tool. The giver said her father brought it back from the war and promised to locate his service information. I purchased and read â??The Lugar Bookâ?� and am still unsure of the history of the handgun. I would appreciate any and all information you can provide and direction to helpful books. To further demonstrate my ignorance, underneath the barrel at the receiver is stamped 8.82. Is that the 9 millimeter designation? I would have attached photographs but don't know how.