[1966burb]

Good morning- I picked up a nice used spare tire carrier for my 1966 Burb. The one end has a bolt with 2 jam nuts. My question is-- are the jam nuts to be tightened up to hold the bolt rigid off of the frame, or left loose so it can swing around a little? The piece between the nuts is an old piece of frame as the guy just used a Sawzall to cut it out. Jim