I've seen men over 60 who have full heads of hair, they just go lucky. Maybe some of them are wearing, but I don't think all of them are. Some of them have more hair than their wives. Thus, I wouldn't say it's completely unnatural for an aging man to have a good head of hair, it's just really lucky. The key, I would say, is to make sure it has grey in it. I had one professor who looked like he had a nice head of hair in his late 50's but it was just so blond that I always suspected it as being fake.