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

My Stage 2 Plus kit includes Wilwood 4-piston calipers and 1" thick 11.75" rotors. See below:

Wilwood Mopar 11.75" Front Disc Brake Kit (Stage 2 Plus)

I missed that. Or I just figured they were the same kit that is on Wilwood's sight.