Joe;

If there has been contact with the cover, I would expect you would see unmistakable signs of it...otherwise, if there is gear wear, it had to come from an interference with something...if you still have the cover off, I'd look around and inspect until I convinced myself nothing serious was happening...

I still don't fully understand exactly where the wear occured...please explain: "tooth damage was most pronounced near the small end of the timing gear". Or maybe post a pic...

Phil;

If a timing gear hub is stubborn to "dissassociate" (great term!) itself from the cam, I have suggested gentle tapping on the end of cam with a soft hammer (while supporting the hub). That has always worked for me (and I've never damaged a thrust plate or popped out a freeze plug)...since the hub is not an interference fit, it will likely "dissassociate" itself, with the slightest impact force...but it is a technique which must be employed with a measure of judgement...hamfisted Chevy mechanics with three-pound hammers need not apply...

Cheers