Had two Prudences, sharded one. The thing is, the Praetorian foil only has a chance to drop in one specific part of the hard mode, whereas faction weapons can drop anywhere as an engram. Pre DLC, not many people ran the hard mode because it was extremely difficult to get to 30, and now not many people run it because the gear is obsolete. I still run the VoG on occasion, I have about 40 clears total, and have only seen the foil drop twice.