Here are three threadless pieces of mine. I need help identifying the one on the far left. I am pretty sure I have identified the middle one as an unembossed CD 731.2. The one on the right is a CD 731 McKee & Co. Is the left one an unembossed CD 731? It matches the size of the CD 731.2 identically, but noticed the curved skirt. And the wire groove is not as pronounced as the McKee. Any help is appreciated. Thanks !!