There are a couple of differences, but they should not present a problem.
You will need to use your old steering gear, idler arm, pitman arm, and center link OR swap tham all to the 73 pieces.
The sway bar, if equipped, is different as are the lower control arms with tabs. The 73-up bar must be used with a 73-up (and MAYBE some late 72) k-member, while the early (67-72) can be used with any 67-76 k-member, but you may have to drill the holes for the k-member mounts.