All that indicates is that the cord was replaced.Also, there is an extra cord for the sensor or cell (the black one for the thee prong connection) right next to the cord that is plugged in, indicating the cell has been changed at least once.
It does not indicate that the cell was replaced.
Most likely, the system stopped working and they replaced the cord to see if that would get it working again.
When that did not work, they decided not to buy a new cell and new trisensor.