To OP's original question though, do recruiters take the possibility that the kid is not physically as mature as other kids in his grade into consideration? For example, in looking at PG grades, they compare your metrics with other people in your grade, some of which could be 2 years older.
It's individual to the recruiter/prospect.
Here's another answer.
Scout "Son, how tall are you?"
Scout "Nobody is 5'11". If I like you, you are 6'0". If I don't like you, you are 5'10"."