Does it have the reinforcing plates?
Here's a picture of a factory bucket seat car, showing the factory reinforcing plates on the inner holes.
View attachment 1715034098
Now, I know that the bucket seat cars came with the bench seat holes, which were then filled with rubber plugs.
***edit***
I went back and reviewed the pictures of my '74 Duster. While I definitely had to add the reinforcing plates, I can't remember if I added the holes or not. They show up as being there in my tear down pictures and I don't imagine I would have added them that early.