I know there are more than just Pretty Vision but she shows up more often than the others with that hoof print. But none of them show up a lot, or are just not really noticed.
I know a few people on here do have Pretty Vision with the circular stamp. I remember LadyG bought one at ponycon some years ago and that's the only one I've seen in real life, but I think I've heard people talking about Curly Locks and maybe Bouquet with it as well?
I think it's because this is the time when Hasbro were experimenting and transitioning pony manufacture between places, but the circle stamp seems to be unique to this set (at least for Chinese made ponies, I think French ponies also have a circle stamp?)