yeh, the frst valve is an ajustable pressure relief valve the input to this comes from the compressor nipple, (to set the anti creep) and the output of this goes to the input of the pressure regulating valve. the output of this goes to the wastegate.

paralleled across the whole setup is a non retue valve (light pressure - norgren do one) to allow the wategate to close quickly one the boost has gone to allow quicker spool up .