I just troubleshooted this... I thought the shop had done something as I just recently had the car repainted, however it turned out just to be the sunroof rail bolts are loose. What you need to do is remove or pull down the headliner of the culprit area (mine was drivers side) and look for a 10mm bolt that's attached to the moonroof rail. Tighten that down, I only torqued mine (I didn't want to go look though my helms at the time, it was 2 am and I couldn't stand it anymore

) to ~10 ft/lbs and the creak went away. I had to tighten it down at two points, I really have no idea how/why it was loose but both of the bolts weren't even finger tight.
edit: checked the Helm's and those bolts are supposed to be 7.2 ft/lbs so I over torqued it a little bit.