Ok so I brought mine in to have this stuff done. I have to go back for the HVAC program because they had computer issues. They said the spoiler and the hoses were ok though. So I opened the trunk the other day and clunk, a nut fell off. Now what.... I guess they overlooked that too.
I got some tubing and stuck a magnet in the end. pulled off two fasteners with part of a ring compression tool I have and fished the bottom of the lid. There is a hole about 3 in in dia under the corner. Success! put the nut back with locktite and tightened the other three with a 10mm socket and some locktite. I still have to do the two center bolts or just have the dealer do it when I bring it back for the HVAC. The plastic fasteners are a pain to get off with care not to damage anything.
I hope this helps out anyone who has a nut rattling around in the lid.