Hmmm, I recognise the stippling on the nocks form flat as the mark of a certain famous amateur gunsmith. I have rifles with similar markings here in Canada.
The stippling appears to be similar to the pattern left as an imprint by the unprotected teeth of bench vise jaws. There also appears to be what could be pipe wrench jaw marks on the receiver ring over that lower serial number.
Bench vise, monkey wrench, sandpaper. Red flag! Check her out carefully JollyGreen, you don't know who has been buggering about with it in the garage and what they might have done.