Odd question about Dusters

Differences '72 and earlier and '73 and later:
1. Spool engine mounts
2. K member changed for spool engine mounts and sway bar change
3. Redesigned sway bar and lower control arm sway bar mount changed
4. Spool transmission mount and crossmember
5. 3 point seat belts (lots of changes due to new mandated safety equip.)
6. Grills
7. Side marker lights
8. Transition to 5 mph impact bumpers front & rear
9. Bumper jack slots in bumpers
10. Electronic ignitions
11. Trunk lid crease added
12. Interior door latch redesign
13. Cardboard headliner
14. Redesigned interior trim = upper door panels, sail panels, ect
15. Addition of Space Duster option (fold down rear seat back)
16. Emissions controls
17. My '74 had big chunks of cast iron bolted to the floor pan and tail shaft. I assume these were for vibration (sound) deadening purposes
18. Hood "ridge/bulge" added
19. No more 8 3/4 rears
20. 4 1/2" bolt pattern only

My brain hurts, someone else take over.......