Dont understand why the OP insist that they were installed backwards, you have the two knuckled tips gone. You can do what you want to do anyways because i have seen it and it will work. The problem is that you risk to damage the threads of axle a little bit. Not the same to have like a head 3 mm in diameter that is flat than have a sharp 1 mm diameter thing in its place.

You can get new parts in the web, those things are still available.