IIRC they removed the unique tag on older rings at the same time that they made old augmented gear the only version of the gear that is able to be purchased, phasing out the ability to buy an unaugmented ring for your second slot. I supposed they feel one unaugmented ring is good enough for current content.

I appreciated back in HW when they let you get the accessories from the proto ultima weekly that matched the ilevel of the best tome and raid gear. It was nice not being stuck with a lower ring.