Well, as a .38 Special, it is not a typical BSR chambered for .38 S&W. However, its serial number is quite low and. early in WWII, I have read that the British were buying up just about any guns they could get. So, it may have been in those early purchases. The US did not implement Lend-Lease until 1941 so the early guns do not have U.S. Property stamps or military ordnance and proof stamps, and received commercial finishes and grips. The Birmingham Nitro Proof stamps indicate it was in British military possession and was proofed when it was sold into the commercial market. I'm not an expert on these or any other S&W guns so perhaps someone who is can give you more relevant and specific information.