Nothing to be concluded from that I'm afraid. Could be a "rack number" added in Britishicon service or who knows what.

The Canadianicon army/ordnance only marked on the right (bolt knob) side of the stocks. Some Home Guard rifles were marked on the left side IIRC, but this isn't one of those.

The bolts often take a bit of a jerk to get started on opening, compared to a regular turn bolt anyway. You could use a fine compound and lap the bolt lugs and breech lugs into each other if you wanted to. I suspect this was what makes the commercial rifles built on the 1910 action noticeably smoother than many MkIII rifles (the military version of the M1910 action)