I don't typically hang meat for more than a day or two, but the only mold I have ever had was when I washed out a carcass with some bottled water I had at the truck before quartering and bagging. Everything the water touched was moldy two days later when I got home and processed it. I just cut a thin slice off that part and no problem.
Some guys might have more info, there are different types of mold on other stuff like kraut and some is fine and some is very bad. I have no idea if the bad stuff can grow on meat or not.