foster said:One other detail about zippers, and I humbly ask to be corrected if I am mistaken, but the early zippers had the rivet for reinforcement, followed by the diagonal stitch in place of the rivet. Some contracts from 1942(?) onward had neither rivet nor diagonal stitch.
The absence of the diagonal stitch on this is another curiosity.
Foster this is correct. From late 1941 some contracts dispensed with the diagonal stitching at the base of the zipper.