The baffle in my 4" kit has the normal coupler, 2 bulk-head plates (1 with a hole for the eye bolt that goes forward, one without that goes aft) and the 2 short sections of tube. If you use the stiffy coupler it goes inside the normal coupler and between the 2 bulk-heads.
There are 3 centering rings in the kit, aft. mid and forward and all 3 should be glued to the motor mount tube. The forward ring has no slots for fins and has the hole for the eye bolt. If you don't install the baffle, you would attach the shock cord to the eye bolt in the forward ring. If you install the baffle, you would attach the shock cord to the baffle instead of the forward centering ring. In both configurations, the forward attachment point is the nosecone. In other words, the shock cord goes between the nosecone and the forward centering ring -or- the nosecone and the baffle.