I worked with a guy who said he served with Stone. (This was at IBM, and the coworker seemed like a very upstanding guy.) My co-worker said that Stone accidentally discharged a grenade lancher into an overhead tree thereby wounding several of his platoon mates. Not sure if this is how Stone got his Purple Heart.
It sounds like the Kerry Purple Heart in Vietnam story. I don’t think it was a real real Purple Heart the way we think they should be given out.