Yes and no, I think the cleric as conceived in D&D would be alien to a medieval audience. The paladin is based on a medieval literary trope but were there ever questing knights in the actual Middle Ages? outside of crusaders?The cleric and paladin for a start. They are deeply rooted in D&D's brand of medievalism.
Ya know if one wants to drop the cleric and paladin for a non medieval game, I see no issue with that.
I will admit that when I think medieval by default I go to the High Middle Ages (1300 to 1500) when feudalism was pretty locked in and some monarchies were starting to centralise.
However, if one goes back to the earlier times it gets more D&D like but never the same. D&D is more inspired by pulp fiction that it is by the middle ages.