Probably better answered by Ed or Steve Loftin.... but (my guess is) that the mount is intact recessed in the roof with a beefed up mounting plate area under the sheet metal to handle the weight, torque and proper final alignment.
Yeah, that's not quite how S&S did it. I guess over the years, the bolts were a little loose, and they put the silicone around it to reduce some vibration. That's kinda lame.Geez... lots of caulking around the C-6!