The top and bottom of the tailstock base, top of the bed (top, front and rear of the ways), bottom of the tailstock, headstock, compound upper swivel, and the two parts of the dove tail should be masked. Those are all critical dimension surfaces. My guess is that all of the castings were painted and then the top and/or bottoms and the dove tails were then machined. Are all of those surfaces masked? The top of the compound slide where the tool post attaches does appear to be masked. Maybe the rest is as well.