I thought it was enough of a callback to Batman Begins that Selina stole the pearls. I didn't need them to be the exact same pearls Bruce's mom had on the night she was killed. Too, being that the Waynes were so fabulously wealthy, it is certainly within the realm of possibility that Mrs. Wayne had more than one pearl necklace in her jewelry box.
Captain Craig wrote:

^^^
Watch it or the morality police from the recent BOTW threads will derail this topic also. 
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Cheap, uninspired potshots are still cheap uninspired potshots.
I guess that's par for the course though.