When I was pulling in with the trailer the other night, I heard a metal clanging noise and noticed this on the ground when I got out. It may have been there prior, but you can anyone verify if this is some sort of shim that goes on the trailer? Or that it is not from the trailer? It doesn't seem like it would be, but I figured if it is supposed to be on there, it might be important. Attached is a picture. Thanks !