Recently purchased two LE turn in 640-1. They are totally different. By different I mean the way they are marked by S&W. Example one has no marking on the left side of the barrel. On the right side Smith & Wesson 357 Magnum is spelled out but it is not deeply engraved as in the case of the other revolver. The # starts with CEU and the other BUA. The CEU also has a mim looking trigger although that could be a replacement. Example two gun has Smith and Wesson spelled out on the left side of the barrel with S&W 357 Magnum on the right. There is nothing in my S&W book that explains this so I thought I would come to those with more knowledge. The engraving on example one is much shallower than on example two