I think that two grains of sand on beaches of the opposite ends of the Earth are probably more likely to interact than a random rock and a tiny satellite that has left the Solar System into interstellar space.
In fact, in about 40,000 years, Voyager 1 will pass within about 1.6 light-years of the star Gliese 445. It's also likely that it's as close to a star as Voyager 1 will be again, ever.
Space is pretty empty compared to Earth or even our own Solar System.