Since this has caused a bit of confusion on the dossier display: Both Jacs have lightsabers that, to a quick glance, look identical. A very close look (requires having attentively observed Jac in combat or practice - something usually only position holders of QUA and up and Elders have done) reveals that for each of them, one has a minor flaw compared to the original, the other looks flawless.

However noticing this will also require that you get your hands on the flawed saber or observe it used in combat. Just seeing Jac pass by with the sabers on his robe will not enable you to make such an observation.