One thing to keep in mind is that they seemed (back then) to be using the word "class" as we would use "class" and "type/role", they had "Constitution
Class", "Starship" or "Star Ship Class", and "destroyer Class" (Kirk's first command). So just seeing the word class on a memo, screen, script you can't say it's class the way we use it. We would say "Centaur
-type" since we don't know the class of the ship, they'd probably say class.