Ferguson was something of a talker. When he was in Dearborn, he loved to play golf with other FMC employees, and told them a lot of things they would not have known otherwise. Ferguson reported to a man named Morgan Geis who was with the SS, who I think made sure he was in DC setting up vehicles for the Army-Navy game that was supposed to take place the following week-end.
https://www.thehenryford.org/explore/blog/morgan-gies-driver-to-the-presidents
How Ferguson walked by the dent in the chrome molding is a mystery to me. He must have put the roof back on SS100X before driving it from DC back to Dearborn, and thence to Hess + Eisenhart for the first rebuild, the "Quick Fix". The garage incident in NYC that Chief Rowley mentions in his letter supposedly happened just a few weeks prior to the Texas trip. Of course, Rowley is making an excuse.
SS100X was the pride of the WHG fleet, much of which was leased or rented from Ford. That being said, there was an earlier FMC internal memo that said presidential limousines did not have to be bulletproof because 'the US is not a banana republic.' How horrifying that seems in retrospect.
The QEII follow-up SS car was bulletproof. However, its top was down, so it didn't really matter. JEH supposedly had a bulletproof car. That would be like him.
But President Kennedy, Jackie and the Connallys were just thrown to the wolves, with no SS protection on the car, even placed at the head of the motorcade instead of in 7h place, as the sticker on a side window says...