I do not think it is a period peice. If I remember right, it was made in the 80's
There was this and another about 7" x 9" paper which was sold at flea markets as a window ad for about $8.00
Your item sold for about $25 at the time
It is an ad for baseball equipment that really doesn't show any
You could check with Tim at
www.thewinchesterstore.com
As he has a listing of every sign made by the company