Hinge pins on a Muscle Cuirass

[Doc]

That is what I said in my post that since hinges are visible on the statues and original artifacts although from an earlier period have them, then it shows continuity and would be as accurate as possible from what we know.
Suppose none of the statues from the Roman period showed a method of closure, what would be the choices? Tie loops, hinges, or buckles the latter of which, to my knowledge has not foundation with musculata. The former two would represent the most reasonable closure methods that would be based on older cuirasses. Thus with respect to the argument of using older armor 100 years later ONLY makes sense if you are talking about an entire piece of armor. I doubt there could be such an extrapolation for a closing method on armor like musculata that really cannot be closed in a myriad of ways. Practically all the armors from BC have hinges or tie loops. Some people say buckles, I do not know of any evidence so I cannot comment.
Being that we do have statues, we can look see persistence and continuity like in the Valentinian statue where hinges are used. However, if you have to choose a hinge, it would be best to use a real attested method not something on a statue. As I keep saying there is evidence that you see but there is other evidence within the realm of what is possible based on the surrounding evidence that is not necessarily implicit.