First visual inspection under light was a possible light SW stamp. This sent up a flag. It looked factory to me by the finish; however under bright light I could see buff markes left and right side of frame.It is important to have a bright light source when inspecting. I knew at this point the gun had been restored in some manner but I was impressed - it was a very good job. Removed grips found the S with a diamond at base of the frame (indication factory blue and factory refin). On frame again under the grip 464 indicating returned to factory for work 4th month of year 1964. Diamond next to serial on barrel and a diamond under the extractor. Very clear..