I had to check the math and I was surprised that 2^42 is “only” 4.4 trillion. Thought it would be a lot greater like there are less atoms in the universe similar to the uniqueness of a shuffled deck of cards.
I typically associate "clone" with "an exact copy", with the same exact molecular layout and even thoughts. So a literal exact copy. Clones on a DNA basis, so something possible for years, would indeed be different in some details.