Aren't redbacks usually supposed to have a stripe? Here in the west we have Western Redback salamanders ( P. vehiculum ) and they almost always have a stripe. I have never found one that doesn't. I don't know much about the eastern species, but I thought they did as well? Though it looks like the northern redback doesn't maybe. I don't know, it just doesn't look that much like a redback to me. Though like I said, I don't know much about the eastern species.
Its a lungless sal that's for sure.