The pistol grip looks to have been reshaped a bit, so I expect the stock markings were cleaned off.
It is a Mk.II***. This is the pattern supplied to the US. I would assume that it is one of those. For a time, the US Rosses were sold off through the CMP. Repro sight hoods have been made.
I have seen a II*** rifle that was not military marked on the butt. It was a presentation rifle awarded in connection with a high school cadet corps.
Usually a commercial rifle will have a serial number stamped with very small numerals on the let side of the barrel breech just above the wood line.
If the bore is reasonable, it should be a good shooter, although the LC doesn't help with reloading cases.