I deleted your thread from the behavior section. It’s too confusing for members to have two threads in different sections.
To answer your question, I doubt there is anything to be concerned about, as long as he checks out healthwise (particularly with his teeth!) I’ve heard of people being pleasantly surprised about their rabbit’s lack of chewing, and then later they discover the reason why they don’t chew is because their mouth is a mess and they physically CAN’T chew.
But as long as he’s eating and behaving normally, I’d say you just lucked out with an easy rabbit. Do you know for a fact he is only 2 years old? Did the rescue have him since he was a baby? If they are going on the word of the people who surrendered him, there’s no guarantee as to his age and he may actually be older, which could explain the calmer behavior as well. Adolescent behavior, even when neutered, can last well into the 2 years of life or longer.