In the glassmaking trade, these seams along with the side mold seams within the finish or just below are referred to as "neck ring" or "neckring" seams since they were formed by the separate neck ring portion of a machine mold (Tooley 1953).
Since its initial posting in early 2005, the Historic Bottle Website has become a very useful resource to the historical archaeology community. It is easier to do this searching before you have opened the bottle. Originally named "Bib-Label Lithiated Lemon-Lime Soda," 7Up became "the third best-selling soft drink in the world" by 1940, according to its current manufacturer, Dr. Bottle and label designs have evolved through the years, but finding the date is simple. Look at the base, or bottom, of the bottle to find the date. If the plant has not printed the date on the base, it can be found on the neck or label of the bottle.These deviations are discussed on the main Bottle Dating page in a box under 4.
"Ghost" seams are usually present on the neck, shoulder, and/or body of the bottle if made by a blow-and-blow machine (like the Owens Automatic Bottle Machine).The side mold seams on most machine-made bottles tend to be finer (narrower and lower) - though sometimes sharper and/or visually distinct than mouth-blown bottle mold seams although many mouth-blown bottles have very thick and distinct seams due to less precise mold construction or fitting.