Consider the typography–bubbly rounded fonts were popular in the 60s. If you spend even a few seconds looking just at the tag, you’ll be able to get a better idea of when the piece of clothing was made.
The more tags you look at, the better you’ll be able to date the clothes and the faster you’ll be able to get through a huge thrift store or estate sale.
I tend to find that there were a few specific companies that were producing their garments with nylon zips relatively early on. I have had five or six dresses by the brand, all with nylon zips and all dating from the late Fifties.
A good way to work out whether the zip in your garment is original or not is to assess the stitching around it. I hope this trip into zips has been useful and informative, and if you are interested in helping to ascertain whether your zip is original or not, please do feel free to contact me!
One of the key reasons for her use of plastic zips was a lucrative deal in 1933 with Harry Houghton of the Lightening faster company to use plastic zips in her clothing.