now that you said about them being brownish, I have seen them too, it still is a star coral, my variety that I had was a pinkish-clear, but like I said I have seen them brown before. The tenticles are slightly fatter than what you would find on a sun coral, and if you look very closely you'll see small pimples on them. Also the mouth of the coral looks a little different from a sun coral. I hope this helps. Like I said before they are fairly easy to keep, just give them some good light and good water, they should keep growing for you.
Matt