From what I’ve read of Rand, she was for individual excellence unhampered by the control of the state. Since open borders usurps and undermines the riights of the individual, I don’t believe Rand would be for open borders.
When Rand writes that one of her characters actually burned down his accomplishments rather than have them taken over by “grabbists”, might we safely assume she DOES BELIEVE in a wall/border of some type? Do we burn down America? Oh the humanity! You produce; you survive and if you must you do everything possible to KEEP your achievements to do with what you wish.