1973-74 B-body vs 1973-76 A-body spindle

Is there a difference between the Disc brake spindles and the upper control arm on the 73-74 B-body vs the 73-76 A-body disc spindles? I'm looking at the Disc brake conversion kit for an A-body from Master Power Brakes and there kit comes with B-body spindles and upper control arms. I already have a set of 73-76 A-body disc brake spindles and I'm getting tubular upper control arms from Firm Feel. If they are the same I'll see if they I can order a kit and they could leave those parts out and hopefully save a couple bucks.

1968 Plymouth Barracuda Rallye Series Front