Yes, this rifle was assembled by Mauser Oberndorf, quite a few were actually as I have recorded good number. When the Arsenal at Spandau dropped Gewehr98 production in 1917 to focus on the MG08 series of machine guns, they sent their receivers to three known locations for assembly. Most went to a facility believed to be a depot in Hannover, but others went to Danzig and MO. The ones made by MO seem to be less common, Danzig about twice as many known, and Hannover roughly the same as Danzig, but probably more.
I made this discovery when I began trending Spandau production some years ago, the right receiver will tell you the assembler between the MO and Danzig variations, other clues also exist (FP, serial ranges, component make up etc..), the Hannovers do not have full acceptance markings and were not assembled in the normal fashion, they are easy to differentiate.
Spandau did not make many Gewehr98's in 1917, many rifles are marked Spandau/1917 but most are not actually assembled there. No 1918 Spandau was assembled at Spandau.
Do some pictures of your rifle, this is another rather difficult variation to find "original-matching", most known are in rough condition.