I've seen a few people mention adding accuracy on these and such.

I can say with almost complete certainty that these relics don't have accuracy and won't be able to add it if we get to customize it. There was a video at one point where the devs said that weapons will no longer have accuracy. It was done so you don't have to replace some armor just cause you got a nice weapon that had accuracy. I don't remember which live letter or video it was however.

Maybe someone with a better memory can quote it for us. I don't really have a memory for dates or video numbers.