If both beings are identical and both have the same memories up to stepping into the teleporter, then "replicaness" or "originalness" is a purely theoretical label that can only be applied by outside observers, and even then only if one steps out of the teleporter before the other, and even then - as with this discussion, probably not without a lot of disagreement.

IDk, it all just seems to reinforce to me how "originality," like the idea of The Self itself, is a very flimsy concept.