I have a pretty early (1931 I believe) DS. On the cylinder latch side the barrel has .38 Detective Special (.38 is full height, Detective and Special are half height, immediately behind the .38). On the other side in very small print is a two lines Colts Pt. Mfg Hartford Ct. USA top line, Pat Aug 5 1884, July 4 1905, Oct 5 1926 on the second line. Total bbl length about 1.92 inches. Barrel extension beyond ejector knob about .36 inches. Mine has silver COLT medallions in the grips.