No Tele kit experience here, but from another thread, it looks like the 'non-G' TL kits have a bridge pickup with a ceramic bar magnet stuck underneath and with steel slug pole pieces. A real Tele bridge pickup will have magnets as the pole pieces - no bar magnet stuck underneath. So if yours has a a bar magnet stuck underneath the bridge pickup, I'd be tempted to swap at least that one out straight away. It's a pickup, but it will never sound quite like a real Tele (though it may sound like the very cheapest of the Squires). But that's not to say that it might sound OK in its own right.

If there's no bar magnet and so the pole pieces are magnets, then I'd give it a go. The GTL bodies are certainly a a step above the TL bodies, so hopefully the electrics are as well. But it's your money and your choice.