FWIW, the Germans did use numerous Mosin capture rifles and also gave tons (literally) the Finns during the war. It's even possible some Mosins would be waffen stamped prior to 1943 when the WaA office downsized and sent 2/3 of it's strength into the army's front lines.
HOWEVER...
A German marked Russian rifle would have to be 1943 or earlier, an M91/30, M38 or M91 or SVT - NOT an M44. It would also be rare and also difficult in the extreme to prove providence for, so therefore wouldn;t command much of a premium, if any.
Show of hands - how many ppl think that rifle's been through a certain gun shop in Alberta???