The inserts and hardware as I understand was ordered through Ford by each dealership and a sub contractor responsible in that region would send the number ordered to the ordering dealership. If the dealership needed more they ordered them again possibly hundreds at a time or if they were not used up the dealership would continue to use what they had in stock until they were used up. So this process would make the style or type a detail not related to assembly plant but to the region of the country where the car was ordered
Hope this makes sense the way I tried to explain it.
Like much of the paperwork, warranty, ownership and safety manuals they were typically placed in the glove box
Will look to see what I have pictures of we, in the past, have found differences between what was supplied ( for example) in the north east and what was sent to California for example.