laguna egr valve

Hi guys. My laguna is smoking. Unbolted the EGR valve and took some doing to get it off. When I did get it off the top part came off and the rest is still inside. It is in two halves, is this is how they are supposed to be as all the photos that I have looked at show it as one piece not two. Also the gasket would not come off and there seem to be brass inserts for the threads for the bolts to go into. I thought it would bolt straight into the manifold. It is a 03 laguna 1.9 dci.