All the parts compared the same in size.
The old idler didn't show any wear from rubbing.
I removed the new idler and then reinstalled it.

I think the inner cover was a touch out of place from bending it up to remove the water pump. After everything was completely finished and buttoned up, the engine started without a hitch and no rubbing was heard. So mebbe I popped the cover back into place?? Or reinstalling the idler did the trick? Or it settled into a new position with a tensioned belt??

Since the top outer cover isn't that big of a deal to get off, maybe an inspection is warranted a week or two down the road??

Ed