Thanks for your input. I have not yet figured out how to post a photo here.The passenger seat and the trunk cannot be installed at the same time on a stock GL. It sounds like you have an aftermarket trunk setback kit installed on your bike to allow this. This is a very popular addition.
If this is the case, there is not normally anything between the passenger seat and the trunk. I have seen some homemade panels installed to plug the gap, though.
Can you post a photo?