Traveller, you are on the right track if you might imagine an older regiment (with more baldies in it) to be more likely to be married and have the head ring than a younger one (the isiCoco is like a wedding ring, it shows you are married) . But it isn't necessarily so. Everyone in a regiment was the same age, and would be given permission to marry as a mark of favour from the king, and then they would all be married together in a mass ceremony. But sometimes a regiment might be withheld permission for years, and a younger regiment allowed to marry instead, because they were the king's favourites.
So it is possible you'd have a married regiment of quite young men, and an unmarried one of older types. But generally it would be the other way around.
Of course some people go bald quite young. My uncle went completely bald in his early twenties.