They can mask off whatever you want. You may notice that I had them mask the sections of pipe on the muffler that the header pipes fit into. It's already very tight and I didn't want fitment problems that required removing the coating, even though a ceramic coating is extremely thin.
Nice, I will have them mask off the ends and hopefully they can get detailed enough to mask off the rivets, or they will need to be taken apart or something... I guess I could always compromise a bit if I need to but ideally I want the rivets still silver.