What you have is a 1918 made Kar98 by Erfurt state arsenal in Germany. The sand blasted receiver is a dead give away of the late war pressures on Germany to produce equipment for the men in the field.
She has the wrong bolt type, it looks to be from a Gewehr 98 judging by the marking. Stock is correct late war style with take down disc and finger grasping grooves. The wood type is beech ("B" on butt), a replacement wood to reduce the demand for already dwindling supplies of walnut.
Erfurt was the highest producer of the Kar98 from 1907 up to 1918. Spandau only made them for a few years, Amberg stopped in 1911 and Danzig made them up to 1913, stopped, and started up again in 1918. Erfurt was the only arsenal to reach double suffix letters for production in one year though visual defects on markings, metal finish, and wood finish were noted as being below that of other arsenals during the war.
The stock has been sporterized, finding a replacement for a Kar98 will be very difficult and expensive as even our American brothers cannot find them. The hand guard is also missing. The rear and front bands alone can command upwards of $100 (last price I remember from E-bay in the U.S.).
Rear sight is original to the carbine.
Barrel matches the receiver so a good chance the caliber is original (7.92x57mm).
I have the distinct feeling she is a vet bring back that was possibly sporterized by the veteran who carried her home.
Do you have a picture of the muzzle end of the barrel ? If the front has been cut off, she will be very difficult to restore.
@draginaru, don't be giving him any bubba ideas

.