Interesting. The SN places it for the period your asking about, but the proof marks really don't. I see marks for the 1925 Rules of Proof and 1954 Rules of Proof. But see no markings for a shot charge or Nitro Proof (the gun was proofed for Nitro, per the BNP and Crown mark). Wonder of the gun was rebarreled.

Best!

Greg


Gregory J. Westberg
MSG, USA
Ret