Looks like a Russian capture (the 'X' on the top of the receiver). The eagle on the barrel (with wings swept down) is pre-war acceptance mark. On the right side of the receiver you have a wartime acceptance stamp (wings spread out with swastika), the small eagles beside with #'s below are pre-war inspectors marks.
Being a Russian capture, the electro penciled #'s, miss-match numbers, painted/varnished wood, missing front sight guard, missing cleaning rod and I will guess two small screws on the trigger guard are absolutely correct for a Russian captured rifle. The Russians stripped them into bits and pieces, inspected and rebuilt them to go into long-term storage as an emergency/war stockpile.
The best thing (as a collector) to do is leave it just the way it is, as it tells a good story. Being an early number it may been there for the invasion of Russia and captured during the German retreat... Who knows what it's seen and done!