I believe you're correct @Johnny Mac. The seat will fit fine, but there are cutouts on the outside corners of the rear seat bottom for the rear seat belts w/ retractors on the later models. I don't remember whether it was 74 or later?
That was it! I think i either removed my seat belts, or they are mashed under the seat because they were too tight to pull up through w/o damaging up the kicker panels i had just painted! thanks!