i believe you don't want anything made before ~78. drum brakes, course spline pinions, the 9.5" diffs aren't said to be any stronger than an 8". basically the axles are identical from 78 on up minus the offset and pumpkin.

on the flat spot on the birfield the manufactures name will be engraved on them.

personally, i don't see a reason to dick with FJ40 stuff when mini stuff is so cheap.