Sorry, I have to disagree with several of the experts; I fully believe it is a factory W/R. I looks like a 50s/60s FN commercial action (NOT a pre-war Mauser Commercial!) that W/R (or an outsourcer- I've seen other makes done up as such) squarebridged. I've seen other W/Rs (and other Brit makes) with that sparce scroll engraving, too, especially during the post-war era. Contrary to popular belief, not all rifles to come out of London (or B'ham in this case!) were 'best' quality. The bolt knob is a bit unusual but this is a scoped rifle and W/R historically changed the bolt knob on their Mausers. I think the scope mounts are factory, if not original (afterall, they went to the trouble to squarebridge the action). The stock also has a monte carlo style to it which also suggests it was built from the ground up as a scoped rifle. As far as the engraving being crude, I think part of the story is the post-war engravers, post-war cost cutting, poor American taste (!), and it looks like it may have been recut when it was wentover sometime in its recent past.
Just my opinion.
BTW, the W/R letters (like any makers) are cool and often filled with little surprises.
A10ACN