Front Suspension Height Adjustment after 1971 Front Drum Upgrade to 1973+ Front Disc Brakes

67-72 A-body LCAs are somehow different from 73-36 A-body LCAs. Does anyone here at FABO who rebuilds LCAs know the difference between the two? I'm asking because the lower control arm pivot point adjusting blade is one of the two measuring points in setting the ride height (the other measuring point being the bottom of the lower ball joint).

My 71 Duster retains its original 1971 LCA, but now has a 73+ disc brake knuckle and bigger lower ball joint installed. If I'm going to set ride height according to the 73+ spec because of the new knuckle/larger ball joint, I'm curious to know what the difference is between 67-72 and 73-76 LCAs and if that difference will affect the ride height measurement at the adjusting blade or at the lower ball joint. Thanks.