As far as we know.
We know quite a bit about the bodies in our solar system. There's not much room for a planet that has geologic processes similar to the Earth and Mars to slip in and not be noticed. In fact, thanks to the very in-depth understanding of physics, gravity and the motions of large bodies, there is exactly zero chance of any planet to exist within our solar system, capable of having rocks ejected that would be similar to anything from Mars.