I have a Service with a SN in the S8000s, which has provenance to late 1937, so I'd date this one approximately to 1938 (probably splitting hairs I know!). I agree with the comments about refinishing, as remember doing so immediately kills the rifle's honest wear and history. All those knocks and wear, where the rifle has been lovingly held and used are gone forever and a large portion of the collecting market will not touch it.

John