No .....
The original SUV was the AMC Eagle.
And the two things that made it a SUV were 4wd and "mom going to the store shopping" level of comfort. The PU truck things were not SUVs.
I should have remembered to include the older Willys Jeep station wagons from back in the late '40s, much taller than subsequent GM/Ford/Dodge/etc. "station wagons." Think it maybe evolved into the old boxy Cherokee or Laredo or some such name...
Seems to me IH Scout started one path, followed by the original Ford Bronco on that same general plan. Then Chevy brought out the K5 Blazer from almost a whole different path, I think built on a short-box half-ton pick-up frame, whereas the Suburban had always been on the regular box pick-up frame (I think). Then the Bronco grew to become a Ford version of the K5 and Dodge made one, etc.
Yes, there was a distinction, much to do with ground clearance and angle of attack and angle of departure and so forth. Even width was a factor, in places like a Colorado "Jeep" trail -- where no kidding sometimes anything wider isn't getting through without a chain saw. (Got our truck stuck on a snowy pass once, literally between a rock and a hard place, because we were both too long and too wide.) Much of the market was about off-roading at best ("sport"), or at least maintaining traction on crummy roads and/or in crummy weather. We had a Jeepster, but I don't remember it being anything other than a 2WD open "Jeep"-like thing, not about the off-road market at all.
The name "SUV" hadn't been invented yet, and I don't think that started appearing until the follow-on crop of smaller truck-based things (e.g., the later little Blazer) came out followed by the crop of car-based "cross-overs" that work OK for going to the Dairy Queen in most weather.
The AMC Eagle was actually pretty good at that... and with a lift kit, usually didn't do too badly on crummy roads. Given AMC's lineage to Kaiser-Willys, maybe the older "station wagon" led to their Eagle concept.
Anyway, now seems to me many of the few remaining truck-based SUVs are more about visibility, and internal space... without much emphasis on traction or certainly not off-roading.
-Chris