David,
I dont think you can be referring to the same coating Celestron are talking about otherwise how can it be transparent?
an exerp from the email from Ozscopes
I have spoken to the service department in detail and the reason why there were markings on the Mirror is because of the manufacturing process. The Mirrors are cleaned before applying the Celestron coating and in the process of cleaning the mirror, the liquid used to clean the mirror may not have been applied evenly. However, they have assured me that this does not affect the Telescope at all. This uneven layer can be found in all Celestron Reflector scopes.
and the Celestron report
http://members.westnet.com.au/rogun/screenies/Celestron.jpg