There used to be cabs with these in bigger cities. I’ve sat in them. They weren’t limos either, just bigger than the usual Checker Cabs. I’m assuming they went along with the Checker Cabs themselves.
Also, a couple things, from someone who personally thinks Oswald acted alone:
Something Oliver Stone kept grinding on was the fact that in the Marines, Oswald was a “marksman.” I’m not completely certain what that term meant in the marines in the 50s, but in the US army in the 1990s, it was the lowest range of scores you could get when qualifying, while still qualifying. The highest was “expert,” and the middle was “sharpshooter.” A marksman could hit as few as 29 out of 40 pop-up targets and still qualify. Hit only 28, and you failed to qualify.
The last was something I know from my family having lived in the Soviet Union in the 1970s.
The US government investigated pretty much every American who went to the USSR, with an eye to seeing if that person might become some sort of informant. My father was actually approached about doing some work. They were kind of like the volunteer firefighters of the CIA.
I doubt Oswald was ever approached, especially after his suicide attempt to coerce the government into keeping him, but the US probably nonetheless had some kind of file on him – and every adult male, and many women who went to the Soviet Union in the 50s, 60s, 70s & 80s.
Conspiracy theorists are kind of like the people who want to prove that someone other than Shakespeare of Avon wrote the “Shakespeare” plays. They know the plays themselves in and out, and the works, and well as what is to be known or their personal candidate, but very little about Elizabethan England, or the literature thereof in general.
I think a lot of conspiracy theorists know tons about the assassination itself, and about Kennedy and Oswald, but not a lot about the US, and the US government at the time.
My father, born in 1930, with a PhD in PoliSci, specializing in the Soviet Union, and a US-born citizen, who had a specific memory of hearing of the assassination, and was watching on live TV when Oswald was shot, always thought Oswald acted alone.