All GWs are built all pretty much the subpar same. The vinyl cap is there to dress up (hide) the seam between the liner and the hull. The side plastic pieces are there to do the same in for the motorwell corners. All are attached with screws into the core which is likely XL Greenwood or maybe a composite for your year. Check with GW Cust Service as the transition was done over a number of years. I'm guessing XL. Marine plywood is probably the worst in this construction followed by XL and composite. The problem with the latter two is delamination not as much rot. (2) motorwell scupper flaps which are screwed into the core as well. One garboard drain that is also in the core. All of these could have been addressed if the areas were holed and solid glass, but that appears to be too difficult for GW to do.
You know the risks, too many screws on the cap and plastic pieces that if breached allow water into the core. The vinyl bang cap is a concern because there is a full length joint that is basically filled with caulk and if breached (which you don't know because the cap is under the motors and only can really come off if you remove the motors. If the boat was stored outside, I'd find out if in a cold area (freeze cycles can aggrivate delamination) and if the boat was shrinkwrapped or properly covered. Check the hard top bottom edge. Look for freeze chips. Water can get in and when freezes it can chip the bottom gel coat off. Look for other coring spots for softness.
It really comes down to was it all done correctly at the factory and did the owner inspect and timely resolve any observed issues. Not something that can be addressed here, I'd get a survey and have a competent person determine if the core is wet or not.