Saturday, December 22: Problem solved. Let this thread die. 
Arrrgh; I swear I've never had an easy set up with
any Kobo ereader.
This time, the Glo. (Bought it today at an Indie bookstore in the US. Yay; finally!)
Long story short, I was continually getting stuck at step 2 in the Set up. The twirling gray arrows. Stuck. I was directed to charge the reader for four hours, and try again. Long story short again, I've tried to get this Glo to work three times, with as many calls to Customer Support. (They've been very helpful).
Finally I gave in to the suggestion to uninstall and reinstall desktop to see if there's some glitch between that and the device.
(I hope it's a case of the desktop, and not the device.
Argggh, I hope I won't have to return it).
Anyway - I'm re-syncing the desktop itself - and now every single book I've ever opened in my Kobo life, including any that I've
finished, shows a bookmark.
Has anyone else gone through this?
P.S. - Dang DSL; 215 books in my library, and Iafter one hour, I'm only up to #107 in the sync. Zzzzz