It is indeed true that Mollies can tolerate full marine. Ideally they should contain salt in their water. Many people use Mollies to cycle a new marine tank as they are cheap and quite expensive (cruel in my view). I would assume they could tolerate a reef setup because they won't eat the corals etc.
/www.fishforums.net/index.php?showtopic=188412&hl=You could have mollies in a reef, but you have to ask the question of why?
There are so many fish that are better looking and more interesting to watch, why would you go to the (often considerable) expense of setting up a reef tank to then fill it with common community fish?
As I say, you can do it, but many consider there to be better fish out there to put in a reef.
ABSOLUTLY not im afraid although mollies need brackish water they wont be the least bit happy in a marine tank sorry but im just saving you a mollie!