67 Cuda bucket seat reupholstery help needed

Finally finished the rear seats, which went pretty well. Now I started the work on the front buckets which are much more difficult.
Bought the seat covers and foam for the front from Legendary...Pearl White.
My question concerns the area on the lower rear section of the seat cover around the post for the seat back. The material does not have an opening in it for the post to go through. The only pictures I have show the material kind of bunched around the post.
Just trying to see if this is indeed how it is supposed to be, or if I should cut a small opening for the post to come through. My fear is that the material will split.
Will try to post pictures later...Larry