I mean, even inside of your body right now, your DNA is busy making copies of itself as part of cell replication. Is the copied DNA fake, but the original was real? The original is a copy too, which originated the same way. Living organisms, at the cellular level, so actively self-copy and self-rejuvenate by piecemeal replacement that it muddies the waters when discussing this hypothetical. Why should it matter whether something is replaced little by little, or all at once?

Change needs time ...