SCP-001 is a special case and is not a single SCP, but rather a collection of "SCP-001 Proposals", which do not compete for 001 but offer alternate interpretations of what could be an 001. Depending on headcanon, they are variably alternate universe occurrences, decoys or fakes, or 001s established before whatever the current system is was developed in-universe. In theory, one, some, all, or none of them could be the real SCP-001.