The five digit number on the yoke and the frame is the assembly number that is used to keep fitted parts together. The large 3 indicates the gun is a K-frame in .357 Magnum caliber. The other marks are fitter and inspector marks that are standard on most guns. No help in determining if the gun is a 19 or a 66. Machining marks do appear on blued and nickel revolvers on the grip frame and this part is not polished like the rest of the gun.

A factory letter will tell you if the gun shipped as a 19-3 or 66, but if it letters as a 19, it still will not answer the question about whether the gun is made of SS or refinished in something like armaloy or metalife. The V on the rear of the cylinder should be easily read, as it the S in the ejector rod shroud. Without those clear markings, the mystery continues.

Bill