You should roll need on items that are an upgrade to you or something that you would use for your crew skills. A greed roll is for something that you would vendor, place on the GTN or an item for one of your companions.
I am 50, another guy in the guild was able to get it but we don't know how. I have also got all the other available datacrons and the crystal from Corellia.
I am trying to pick this up in the museum on the Ziost Shadow but am getting the message "you require more experience to use this".
Does anyone know what you need to do to get this or is this just a bug?