OK, after a bit of a delay I've had a close look and took a picture of the interior.
First my scope is stock with the exception of a Feathertouch SCT microfocuser and a set of Bob's Knobs ... it is as it came from the factory in 2006. It is a black tube model purchased as part of a C6-ASGT package. Visually through my C6 I do not see the ring you described when viewing Jupiter. I would class the optics of my scope as very good, it is an excellent example of a SCT. The views of Jupiter on nights of very good seeing rival those through my TMB115 refractor.
The picture clearly shows a few things ...
1) The factory applied flocking is an adhesive material applied to the inside of the baffle tube ... it is not sprayed on or anything like that. This is clear from the gap as well as the upper edge, that white ring is the adhesive layer.
2) The flocking of the upper inside of the baffle tube goes all the way to the outer edge ... no shiny ring on the inside of the baffle tube.
3) The flocking in my scope is not "complete", there is a gap between the edges visible as that darker line. This line shows up in my star tests as a small "bump" in the outer fresnel ring.
4) The baffle tube itself has ridges in it as well. This isn't that easy to see in the image posted here but is clear on the full size image that came off the camera.
5) The flocking shows up a bit lighter than the rest of the interior of the baffle tube with the flash.