Actually, The neck joint on a strat has a rounded heal and the heel on the Tele Neck joint is flat. You can put a a hard tail on both strat and a tele and the tele will still sound like a tele. It is the neck joint that is why a tele sounds the way it does and the strat sounds the way it does. I have a tele (flat heel) with a tremolo and it still sounds like a tele.
The characteristic sound comes from the neck heel shape