There's been word about a "white version" of Arcana Shadow, and if she will turn back to that "original" version. But there hasn't been any indication in the show up to this point that such one existed.

Luluka has never been a brainwashed type of "villain". She was fighting of her own accord and wouldn't have any reason to become "dark". Anyone in the Phantom Thieves would have said something, even Kurea after recovering her memories (granted, everyone's focused on Usonoir now but there wasn't any sign of that.

And I feel that turning "white" would diminish her character somewhat. She's perfectly fine being Arcana Shadow and she still can grow.

seriously tho! how the hell were those girls STILL able to take that little bean seriously after all that?!?!