Replicating Probes Are a Great Way to Explore the Galactic System

In interstellar travel, one of the best ways you could explore the galaxy is by not sending an individual ship to every star system. Replicating probes are thus a really great way to explore the galaxy. If aliens came to visit us and made a bunch of stuff, what once they got here? It would have the same isitope ratios that you would expect in our solar system. And as a result, having isitope ratio would not prove that the material was produced by humans. Are there ways you could try to settle whether such material was made by extra terrestrials or by us? Potentially, there are ways. For example, we have recently developed some meta materials that