I'm assuming this is a full leaf pack? depending on the age you may be able to read the numbers on them. I bought a used RE 4.5", the part numbers as well as the RE stamp were evident and I found it was just that.
Second question would be why do you need new leafs?
And if the 1/2" is so noticeable then you can get a spacer for front or shackles with adjustments.
84 xj 350tbi, sm465, 203/205, 60/70. links and other junk.
what size sawzall blades does it take to fit 40's?