It's an LSA barrel, whenever it was installed (FWIW, the only 39 I see is on the LSA inspector's stamps). LSA didn't date their barrels. My thinking is running along the lines of original barrel. I've got a CLLE with an LSA replacement barrel, and it's dated to the conversion...the LSA inspection stamps appearing noticeably older than the date.

It's certainly possible that it was an interwar replacement (EFD Inspection stamps), but I'd have thought it would've picked up a date at the time.