uh, stanier, that is an original 1942 closed end crown zipper that you ear marked on worth point. i know because it is one of two that i sold on greedbay recently. they came from trashed wwll shearling overalls. of note is the fact that during the wwll period three models of crown chevron zippers were made. the first was a chrome plate puller and teeth [gimped] with the puller head being flat, and the head not as pointy as the next two models.. the second was also chrome plated with the puller having the ridged head and pointier then the first as seen in the pix above [the most common type]. the third model was designed the same as the second, except that the teeth and stopper were made of zinc and puller zinc plated. because all of the crown zipper used a unique process of fusing the teeth to the tape, called gimping [look closely at the tape and see the metal thread running through it at the area where the teeth are fused to the tape]. this process may be the reason for crown zippers to come undone over time....and the zinc models disintegrating due to contact with salty air, water, urine, etc. oh, and welcome back, kotter.