No, but . . .
An older teen
with lots of leg hair surely had much less leg hair 2-3 years earlier, when he was just starting puberty
(and his penis, testes, and scrotum were beginning to enlarge).
Now the teen is hairier and further along in puberty, so his penis is much bigger. However, when comparing different teen boys, the amount of leg hair is genetically-linked, and not related to the size of body parts.