Those are both great guns; thanks for letting us see them.

While there were a few K-38s in existence in 1947 for testing and marketing purposes, actual commercial distribution of these guns began in February 1948. The four- line address block on yours means it was assembled after April in that year. The target hammer on yours was probably not available until late 1949 at the earliest (and likelier, early 1950), so if it is original to the revolver the gun is a little younger than you thought it was. If the gun's serial number is below K75000 (late '49, roughly), it probably shipped with one of the new-profile standard K-frame hammers (AKA the "sculpted" hammer) in 1948 or 1949. The target hammer would have been dropped in later.

If the gun's serial number lies between K80000 and K100000, it is likely to have shipped in the course of 1950. As always, a solid and reliable answer will require a letter from the S&W Historical Foundation.

My miserable eyes can't see the barrel profile well enough to tell if that is a wide-rib or narrow-rib barrel (also called "heavy" and "light" (or sometimes "standard"). If it's a heavy barrel, it is close to impossible for the gun to have shipped before 1950.

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David Wilson