Working down the list of running changes that took place during 1965 production at San Jose as the title states, in this thread I focus on spare tire mounts and hardware versions.
When production of the Mustang began plants started out building Mustangs welding a small sheet metal bracket to the passenger side of the trunk floor that held a carriage bolt that was used to secure the spare tire to the vehicle. Later in production the bracket and hardware changed to a version where a J shaped threaded rod was installed to hold the spare tire in place and the bracket welded to the floor was shaped to form a loop for attachment purposes.
Early Carriage Bolt/Slotted Version
Later J Hook/Loop Version
Looking my collection of pictures and VINs I found the following.
Highest sequential VIN's with the slotted bracket that I have picture of - 5R17621x
Lowest sequential VIN's with the loop bracket that I have pictures of - 5R17624x
That produces a very narrow range between the highest and the lowest of each group. With these new data points it appears at this time that the change over was around Jan 19th a narrowing from the earlier posted mid Jan to mid Feb 1965 at San Jose
Hope this helps others in their efforts and projects.