Yes from the factory that steering stuff is different. BUT you can change the K-member indepedently from the steering gear and linkage. The 68 steering box, pitman, idler, centerlink will all switch over AS A UNIT into a 73-76 K-member.
I ran 73-76 steering box, pitman, idler, and centerlink in a 68 K-member (68-72 style) for years.
When you get the 73-76 V-8 A-body K-member, get the strut rods with it. IIRC, they are a little differnet length.
Hotchkis sells sway bar brackets you can weld to your current LCA for $29.95. Early or Late style. But they have them listed under the B-bodies. Same bracket used on both cars.