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Looking at Realoem.com, it seems no. I think it is just a ball and socket arrangement with no gasket. The nut looks ugly in the photo, but the OE nuts are copper and they came off my N52 pretty easily with a impact wrench (I didn't try without the impact). The stud is also replaceable, but it is knurled, so it won't come out easily.
Safe approach in this case is having a bolt extractor set, for me size 11 and 12mm saved the day, studs were in very good condition so only replaced 4 bolts with new ones.
My Ride: 2010 535xiT Touring, N54, Individual Audio
Model Year: 2010
Engine: N54 3.0L Twin Turbo
Mine were like that the first time I took my exhaust off. Start with lots of PB Blast and some heat from a torch. I managed to impact mine off with a smaller 12 point socket - see photos.