i have a 55 second series 3100 and i when and baught a better bed off of a 57 3100 ok everything ok the front brace where it bolts to frame the two middle ones are ok and bolting . but heres my question ok at the rear of the bed where the rear bed brace is and the frme rail ends theres two ears there where bolts go down threw but heres the thing the ears and my rear frame rails are not matching up the so called ears are 3 inches over from the ends of my frame rails so its leaving me where i caint bolt the rear of my bed down . i have notthing to go on for as when i baught the 55 it had no previous bed on it and i found the 57 and i was told its the same what could be wrong ?????