Dale, I do not know why but the round holes are factory. My guess is that they broke the tool that was used to punch the oval holes and just drilled them until it was replaced. The #3 1/2 Newhouse also has that model with the round holes. All of them that I have seen have the last model "pat." pan without a date, "made in USA" spring stamp and split jaw posts.
You just made my day better Dean... I paid up for the round hole one in hopes it was a factory thing and I've only seen a few others like it. Never saw a #3 1/2 like that till now. Thanks for the info.....
Here's a #2 1/2 that is basically the same except regular slots and no split jaw post...