Will the upper and lower door hinges off of a 74 work on a 72
Yes . You can even use the 75 - up B Bodies .
Thanks wasn't sure they looked similar but have different part number stampings
The change in part numbers i believe came because of the change in body styles or a slight modification of some kind . The 71 - 73 used a Coil spring in the lower hinge and I think starting in 74 they went to a S - type spring .