As seen in the answers to In Star Trek, does the original die in teleportation?, transporter technology in The Next Generation reconstructs a person at their destination using, at least in part, their original particles, making it easy to believe that you get the same person at the start and finish of transportation, rather than a copy.
I'm sure I have heard that this was a deliberate change to how the transporters worked in TNG, to eliminate all of the philosophical questions about whether it's still you or just a copy that arrives at the destination.
All references I can find on how the transporter works (both here and at memory-alpha) cite TNG or later.
So, my questions are:
- Did early transporter technology work in a way that made it less clear whether the destination receives the original or a copy?
If yes, was that still true for early transport of humans?
If no to either question, is that consistent with how it was portrayed in ToS or is it a retcon?