The torque tube style rear end used springs with an offset pin as it has a pivoting mount that moves the rear end to a more centered position. On a 55 1st series, the leaf spings had the locating pin centered to put the open drive-shaft rear end in the correct location. That relocating bracket looks pretty good. If the springs are at all questionable, ESPO https://www.springsnthings.com/leaf-spring.htm makes a great and affordable spring. You could just have them made to the 55 1st style.