The wig has tabs in the back to make it smaller or bigger.
In 1970 I got a job selling Gabor wigs in a big department store. Sam had mentioned they started 51 years ago so that sounds right.
I was a hairdresser at the time and got hired b/c of that. I had to wear a different wig every night I worked and it was a lot of fun. I would wear the wig out at night for fun. Of course they looked more like wigs back then but they look pretty good now.