The reason im asking is because i heard some where that they have something on them that isnt safe for reptiles/amphibians but im not sure if it was true.
I've never heard that before. I know where I work (not a pet store) we have some snakes with live and fake plants in their enclosure, not leos but at least its a reptile. I'd say be safe and if it looks like it has a waxy film that you or your leo could scratch off or is cheap and the leaves could pop off then don't get it.
Keep looking to make sure that the fake plants don't have something on them bad for leos, better safe than sorry.