During puberty a boy's testes and scrotal sack grows, his pubic hair develops, his body grows and develops, his penis size increases, facial and under arm hair appears and his voice deepens.
As the male progresses through puberty, testosterone stimulates the development of male secondary sexual characteristics such as the facial hair and the growth of the penis. So yes, the appearance of hair around the body demonstrates the presence of secondary sexual characteristics which include the growth of the penis and facial hair. This means they are in the advanced stages of puberty.
Keep in mind... Some people are more hairy than others because of genetics and family history.