They may be using an HVLP (high Volume, Low Pressure) rig, the new-age replacement for compressed-air cup guns. A lot of the painters I know have switched to PPG automotive paints for high-end work. A good HVLP can cost you, though...
...A lot of this kind of finish work is done in a shop instead of onsite. Dunno anyone using Bondo to fill grain and scratches though...Good old cabinet makers' grain filler has always worked for me, though I use Crawford's Painters' Putty for nail holes.