Brake Changes on A Bodies

The slant six cars were standard with drum brakes, front and rear even through late 1975. I'm told that January 1, 1976, New cars sold in USA had to have front disc brakes.
I once had a 1976 Dart Swinger....225 slant six, 904 and 4 wheel 9" manual drum brakes. If it was original, it would have had to be built before the end of the year 1975. It looked original. It had rubber floor mats and an AM radio. It was pretty basic.
I've mentioned that car numerous times and have had a few argue that the car could not have been built that way. Since I did not order the car and own it since it was new, there is no way to know for certain that it was 100% stock but in my years of junkyard crawling, I've seen many 73 and later A bodies with 4 wheel drums. I had a slant six 73 Dart Sport with 10" front, 9" rear drums. I had another slant six car...a 74 Dart Sport with 4 wheel 9" drums and 14x4" steel wheels. I've never seen a 4" wide 14" wheel before....that was a weird one.
Usually, the 318 cars had 4 wheel 10" drums as standard.