I know for a 54 3100 the license plate bracket is suppose to mount in the middle. The bumper of a 54 should have about a 20 inch wide depression along the top of the bumper in the middle that is there to allow you to see the license plate.
Wait, as I was typing this I just realized my 54 does not have the correct bumper. I don't have the depression. Now I am depressed.
54 rear license plate bracket with light
