If it says "Mod 98" on the left side of the receiver, it is/was a German K.98k (Karabiner 98 kurz), the standard German service rifle of WWII. There should be no wood between the rear of the rear sight and the receiver.
The rifle was rebuilt and refinished at the Zastava factory at Kragujevac in what was then Yugoslavia (now Serbia and Montenegro). The factory was known as "Factory 44" during the Communist era, and was also the plant that built the Yugo automobile and the Model 48 rifle, a modified Mauser 98 with a short receiver.
The Yugoslavs removed the original maker's mark, and removed or defaced all swastika markings. Most were "forced matched" with parts renumbered with a stamp or electric pencil after reassembly.
If the rifle is in good condition, it should be a good shooter; it has a moderate collector value, but nowhere near the value of an original and matching K.98k that has not been reworked.
Jim