Upper ball joint measurement

I have a set of UCAs from a 74 Duster drum brake car. I was told that ALL 73 & up A bodies have large ball joints as opposed to 72 & down cars. Is the tapered shaft that goes into the spindle bigger in diameter than the 72s & down? How do I know for sure which ball joints I have. According to RockAuto, the Moog part #s are different from 72 & down to 73 up cars.
I need to know for sure before I can sell them honestly.
Thanks