We got an extra point for “honors” courses, so your GPA was based on how many honors courses you wanted to take. I had a GPA above 4 but was barely in the top 5%. That was in 1977.
In fact, I audited a debate class my senior year, turned out I was pretty good at it, my partner really better, and we won the novice category in our state. Teacher decided to reward me by making me official and giving me an “A” in the class.
That pulled my GPA down.
My late wife graduated from a large State University with a 3.97 GPA. She totally earned it.
At that time it was impossible to get a score above 4.0.