Theres 2 main forms of sandblasting.
Sandblasting will remove rust but they generally will not use this on panels because the heat produced will distort the panels
Beadblasting is a less abrasive form of sandblasting and will remove paint without creating too much heat or distortion, there will be small amount that may be noticable to the panel beater who picks the car up afterwards.
With my car they sandblasted the engine bay, under panels, wheel wells and door jams then bead blasted the rest. Unless you had huge amounts of rust (eaten away sections of metal) the sandblasting shouldnt punch too much out. If it does though its probably for the best because you'll need it plated anyway.