Let?s assume the brackets are the same part number and different stamping plants had slightly different designs. If that were the case these brackets would be mixed up and we would see notched versions on the top side. Have you ever seen a notched version on the top?
Honestly have not looked for a spare tire bracket with a "notch in the edge" Looks like a that may have been designed for a different application, possibly made to be in the reverse so that the hook stays centered and the bracket mounted on its side as attached in the examples. If this is the case then this suggests a different non-Mustang application, another mistake, as PraireBronze posted. If so then it would have a different part number. All you need do now is to look at other models built on the same line or another in the building to see where someone screwed up.
............... When you see a ?mistake? repeated over and over at two different plants at two different times with two different sets of workers does it not make you question was it really a mistake?
Yes when you see tens of thousands or more without the same mistake. If its not a mistake why were not all the cars built with two retainers?
Can offer many other mistakes that were repeated at different plants by different workers so this is not the first or last one. In everyday life we see different people making the same mistake every day in the news. Same thing.
Not sure that the discussion is going anywhere at this point