Hi Aprianto,
You can have the mesh welded or not, depends if you want to deal with separate geo wich can be useful sometimes. You can always combine it in maya later.
Any yes the exported mesh already has uv's.
Good luck with the tutorial.
David
From a readers' Q and A column in TV GUIDE: "If we get involved in a nuclear war, would the electromagnetic pulses from exploding bombs damage my videotapes?"