Not to be difficult, but I think too much is being read based on just footers right now.
Most Mack coasters have squared footers without a circular post. B&M does mostly pure squared footers. Intamin does the combination squared and round.
Is that to say an OEM can’t change the footer pattern? No, not at all. I honestly don’t think you can take much on the footer pattern until we see the bolt pattern. That’s the spot where OEM’s tend to be more distinctive. And while Mack is the leader in free spin cars, remember that Intamin, Gertlauer, Maurer, and Zamperla also make spinning models.