I'm not up on my fashion terminology, but it seems like "Line for line copies" would mean knockoff of famous designers?
The dresses have a Talon Zephyr zipper, which must have had some cache. Their wiki page seems to be based on company PR:
Talon Zipper is a company founded in 1893, originally as the Universal Fastener Company, in Chicago. They later moved to Hoboken, New Jersey, and finally to Meadville, Pennsylvania. It was in Meadville that the zipper as we know it was invented, until then they were producing hookless fasteners for boots and shoes. Here, the zipper was mass-produced beginning in the 1920s.
But that was before it was swamped by the YKK juggernaut.