I am going to venture a guess.... green branching acropora?
Seriously though I think it is hard to say. I have seen 3 different slimers and they all look different. There are so many species of branching acropora and I'm sure a lot of them come in green.
Honestly the only thing I noticed about mine is it actually is really slimy to the touch! Does the new one feel slimy? Did it produce much slime when you put it in the tank?