Perhaps not weird when you consider a punch press and dies set-up for production efficiencies. In the general scheme of things that small hole may not have been worth additional or different tooling. Production levels for many of the AD years exceeded 300,000 units.
Here is the step install directions which had not worn the years well, the measurements fortunately could be saved.
https://www.flickr.com/photos/advance-design_parts_co/16023979479/in/set-72157631868452754