Back to the original question about identical aircraft:
A general point: no two airframes or engines are identical, even off the same production lines, as all engineering products are built to defined acceptable tolerances.
From my experience, a couple of examples:
First, on a Hunter squadron, we had one particular FGA9 airframe that always burned more fuel than any of the other dozen or so, even after more than one engine change. For some reason that was never never established its drag must have been higher than the norm. Usually, after we learned that fact, it was flown as a formation leader, but even so was often most limiting on fuel of a 4-ship. XF442, also famous for another unrelated reason.
Second, some years later, in a fleet of 20+ B737-200, there were 2 airframes (built consecutively at Boeing) that had much heavier ailerons than the rest of the fleet. When snagged (more than once) the response was always "ground tested and control forces within limits".
So, yes, they differ.