I worked on some Camaros, Z28s etc of that era when they were new, but I don't recall such insignificant details as the 'wire separators)..
.. actually, I have trouble remembering some much more significant things after all these years!
Regarding such items as these wire separators, for myself and many others I'm sure, the first time we work under the hood, changing plugs, wires, checking our oil, etc... we likely would reroute wires to be more consistent with where we think they should be (depending on our own viewpoints, etc). When we change wires or plugs, those separators break, fall off, or don't get put back on (they've been referred to as 'mickey mouse!'), none of us ever intentionally removed or didn't re-install items that we considered to be 'mickey mouse' or unnecessary, did we? (thinking about the smog stuff right this second!)..
Yet now 47-49 yrs later, we're trying to determine if the factory *really* put them on every car??? hmmmm..
as Paceme Steve stated, we have to go by the 'standards' and documentation we have which is what the factory used; whether every single car got them or not... who knows? I challenge anyone of you to prove your car did not get them! I'm really waiting to see the proof that Austin can come up with to 'prove' his car didn't come with them...