Something to bring up with the mods, maybe. There's usually only one of each unique allowed, I think, but I think you could make a solid argument for it as it was in your possession.

It's probably a slot, same as my armor was. The add-ons would be useless without an AI to run it, and the mods have previously ruled that Epsilon is well-rounded enough to be apped on his unknown, unlike other fragments like Theta and Delta.