Do you have to swap K members for /6 to SB?

One thing I found out when the shop putting my car together did it is that there are differences between a 73 and a 72 K-member (my car is a 73 and he had a 72). The lower control arms didn't mount in the same place (had to get 72 arms) and they changed power steering pumps in 73 so he had to get a custom hose or something for my pump to work.