ummm i kind of think that at tylers age its still ok especially if he is just curious - i wouldn't start changing somewhere else in case he felt he was being naughty or something for looking. i would maybe take the opportunity to talk about boys and girls being different, and maybe just explain that now you understand boys and girls are different, it isn't nice to poke/stare at other people's bodies.....
he might be a bit young yet for that though im not sure!